Transient Liquid Pressure Power Generation Systems and Associated Devices and Methods

ABSTRACT

A transient liquid pressure power generation system and associated devices and methods is disclosed. The system can include a liquid source and a transient pressure drive device fluidly coupled to the liquid source to receive liquid from the liquid source. The transient pressure drive device can include a drive component, and a transient wave or pressure producing element to cause a high pressure transient wave in the liquid traveling toward the liquid source to operate the drive component. Additionally, the system can include a heat source fluidly coupled to the transient pressure drive device and the liquid source to receive liquid from the transient pressure drive device and heat liquid returning to the liquid source.

PRIORITY DATA

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/928,663, filed on Dec. 16, 2010, which claims the benefit ofU.S. Provisional Patent Application Ser. No. 61/284,632, filed on Dec.21, 2009, each of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to liquid power generationdevices, systems, and associated methods. Accordingly, the presentinvention involves the mechanical arts field.

BACKGROUND OF THE INVENTION

Devices that use repeating transient confined liquid pressures (such aswater hammer pressures) to do work (as defined in physics and having thesame measurement units as energy, termed herein and throughout simply as“work”) have been in existence for over two centuries. The first appearto have been water hammer type pumps, known as ram pumps, that pump aportion of the water entering the pump to a higher elevation using theliquid transient pressures created within the pump. Ram pumps operatemost efficiently where conditions of water flow and upstream water fallor head and downstream water lift are in suitable proportions. Further,ram pumps operate in rather limited circumstances and typically have asubstantial waste flow component typically pumping only 10 to 25 percentof the water which enters the pumps and releasing the remaining 75 to 90percent of the water to waste. Thus, ram pumps are notoriouslyinefficient in terms of the volume or flow of water needed for theiroperation in relation to the volume or flow of water actually pumped.Therefore, ram pumps are rarely used for pumping liquids other thanwater.

SUMMARY OF THE INVENTION

Although known devices of various descriptions use repeating transientconfined liquid pressures to do other forms of work, these devices lackefficiency and can waste resources. Recent research by the presentinventor accomplished in the development of the systems, devices, andprocesses disclosed herein has demonstrated improved efficiency andreduced or eliminated the waste of resources.

Accordingly, the present invention provides a transient liquid pressurepower generation system and associated devices and methods thereof. Inone aspect, for example, such a system may include a liquid source and atransient pressure drive device fluidly coupled to the liquid source toreceive liquid from the liquid source. The transient pressure drivedevice can include a drive component, and a transient wave or pressureproducing element to cause a high pressure transient wave in the liquidtraveling toward the liquid source to operate the drive component.Additionally, the system can include a heat source fluidly coupled tothe transient pressure drive device and the liquid source to receiveliquid from the transient pressure drive device and heat liquidreturning to the liquid source.

The present invention additionally provides a transient liquid pressuredrive device. Such a device may include a liquid conduit fluidlycoupleable to a liquid source to receive liquid from the liquid source,a drive component operable to generate power from a transient pressurewave, and a transient pressure producing element operable to cause atransient pressure wave in the liquid to operate the drive component.

The present invention additionally provides a method of generating powerwith a liquid. Such a method may include obtaining a liquid having apressure or velocity, conveying the liquid through a conduit, causing ahigh pressure transient wave in the liquid within the conduit, utilizingthe high pressure transient wave to perform work, and heating theliquid.

There has thus been outlined, rather broadly, various features of theinvention so that the detailed description thereof that follows may bebetter understood, and so that the present contribution to the art maybe better appreciated. Other features of the present invention willbecome clearer from the following detailed description of the invention,taken with the accompanying claims, or may be learned by the practice ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a transient liquid pressure powergeneration system, in accordance with an embodiment of the presentinvention.

FIGS. 2A-2C are schematic diagrams of components of a transient liquidpressure power generation system, in accordance with an embodiment ofthe present invention.

FIGS. 3A-3C are schematic diagrams of components of a transient liquidpressure power generation system, in accordance with another embodimentof the present invention.

FIG. 4 is a schematic diagram of components of a transient liquidpressure power generation system, in accordance with an embodiment ofthe present invention.

FIG. 5 is a schematic diagram of components of a transient liquidpressure power generation system, in accordance with an embodiment ofthe present invention.

FIG. 6 is a schematic diagram of components of a transient liquidpressure power generation system, in accordance with an embodiment ofthe present invention.

FIG. 7 is a schematic diagram of components of a transient liquidpressure power generation system, in accordance with an embodiment ofthe present invention.

FIG. 8 is a schematic diagram of components of a transient liquidpressure power generation system, in accordance with an embodiment ofthe present invention.

FIG. 9 is a schematic diagram of components of a transient liquidpressure power generation system, in accordance with an embodiment ofthe present invention.

FIG. 10 is a schematic diagram of components of a transient liquidpressure power generation system, in accordance with an embodiment ofthe present invention.

FIG. 11 is a schematic diagram of an aspect of the transient liquidpressure power generation system of FIG. 10, in accordance with anembodiment of the present invention.

FIG. 12 is a schematic diagram of components of a transient liquidpressure power generation system, in accordance with an embodiment ofthe present invention.

FIG. 13 is a schematic diagram of components of a transient liquidpressure power generation system, in accordance with an embodiment ofthe present invention.

FIG. 14 is a schematic diagram of a transient liquid pressure powergeneration system, in accordance with an embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION Definitions

In describing and claiming the present invention, the followingterminology will be used in accordance with the definitions set forthbelow.

The singular forms “a,” “an,” and, “the” include plural referents unlessthe context clearly dictates otherwise. Thus, for example, reference to“a valve” includes reference to one or more of such valves, andreference to “the conduit” includes reference to one or more of suchconduits.

As used herein, the term “about” is used to provide flexibility to anumerical range endpoint by providing that a given value may be “alittle above” or “a little below” the endpoint.

As used herein, the term “substantially” refers to the complete ornearly complete extent or degree of an action, characteristic, property,state, structure, item, or result. For example, an object that is“substantially” enclosed would mean that the object is either completelyenclosed or nearly completely enclosed. The exact allowable degree ofdeviation from absolute completeness may in some cases depend on thespecific context. However, generally speaking the nearness of completionwill be so as to have the same overall result as if absolute and totalcompletion were obtained. The use of “substantially” is equallyapplicable when used in a negative connotation to refer to the completeor near complete lack of an action, characteristic, property, state,structure, item, or result. For example, a composition that is“substantially free of” particles would either completely lackparticles, or so nearly completely lack particles that the effect wouldbe the same as if it completely lacked particles. In other words, acomposition that is “substantially free of” an ingredient or element maystill actually contain such item as long as there is no measurableeffect thereof.

As used herein, a plurality of items, structural elements, compositionalelements, and/or materials may be presented in a common list forconvenience. However, these lists should be construed as though eachmember of the list is individually identified as a separate and uniquemember. Thus, no individual member of such list should be construed as ade facto equivalent of any other member of the same list solely based ontheir presentation in a common group without indications to thecontrary.

Numerical data may be expressed or presented herein in a range format.It is to be understood that such a range format is used merely forconvenience and brevity and thus should be interpreted flexibly toinclude not only the numerical values explicitly recited as the limitsof the range, but also to include all the individual numerical values orsub-ranges encompassed within that range as if each numerical value andsub-range is explicitly recited. As an illustration, a numerical rangeof “about 1 to about 5” should be interpreted to include not only theexplicitly recited values of about 1 to about 5, but also includeindividual values and sub-ranges within the indicated range. Thus,included in this numerical range are individual values such as 2, 3, and4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc., as wellas 1, 2, 3, 4, and 5, individually. This same principle applies toranges reciting only one numerical value as a minimum or a maximum.Furthermore, such an interpretation should apply regardless of thebreadth of the range or the characteristics being described.

THE INVENTION

The present invention relates to a transient liquid pressure powergeneration system, and associated devices and methods. With reference toFIG. 1, illustrated is such a system 1. The system can include a liquidsource 10, a transient pressure drive device 15 fluidly coupled to theliquid source, such as by a conduit 11, to receive liquid from theliquid source. The transient pressure drive device can be configured tocause a high pressure transient wave in the liquid traveling toward theliquid source to operate a drive component 15 a of the transientpressure drive device. The high pressure transient wave can be caused bya transient wave producing element or device 15 b. In one aspect, atransient wave or pressure producing element or device 15 b can functionto stop or slow liquid flow. In another aspect, a transient waveproducing element or device 15 b can cause an impact with the liquid. Inyet another aspect, a transient wave producing element or device 15 bcan function to cause a rapid release of pressurized liquid into astationary liquid. A transient wave producing element or device 15 b cantherefore include a valve, a piston, or any other suitable transientwave producing element or device in accordance with the presentdisclosure. In some embodiments, a drive component 15 a can function asa transient wave producing element or device 15 b, or vice versa.

In some embodiments, the drive component can be operably coupled viacoupling 17 to supply power to a device 16. Additionally, the system cancomprise a heat source 13 fluidly coupled to the transient pressuredrive device and the liquid source, such as by conduits 14 and 12,respectively, to receive liquid from the transient pressure drive deviceand heat liquid returning to the liquid source.

The high efficiency confined liquid transient pressure work/energyprocess can include components whereby any liquid from the liquid source10 can be released or pumped into a conduit 11, or other suitableconveyance component, and the confined flowing liquid can be conveyed ata velocity to a downstream transient pressure drive device 15. Theliquid can enter and pass through the transient pressure drive device15. As discussed further hereinafter, the transient pressure drivedevice can have any suitable configuration and construction that canrepeatedly produce transient high and/or low pressures in the liquid andcan cause the transient pressure to drive the device 16. The device 16can be directly or indirectly connected to the transient pressure drivedevice component in any suitable manner via the coupling 17. Thetransient pressure drive device component can produce the liquidtransient high and/or low pressures, for example, by repeatedlystopping, substantially slowing, turning, or partially obstructing theliquid flow in any manner. Liquid flowing through and exiting thetransient pressure drive device can thereafter be conveyed to the heatsource 13 in any suitable manner, such as by conduit 14. The liquid flowcan then return to the liquid source or directly to the conduit 11 inany suitable manner, such as by conduit 12.

In some embodiments, conduit 12, conduit 14, and/or the heat source 13can be omitted from the system if liquid conservation is not needed fora particular application. In this case, the liquid flow can be releasedto waste from the transient pressure drive device 15 rather than beingreturned to the liquid source 10 via the heat source.

It is well known that confined flowing liquids within closed conduit orpipeline systems can undergo rapid changes in pressure, density, andeven flow direction when the velocity of the liquid is either increasedor decreased. These pressure and density changes are known as hydraulictransients because of their transient and temporary nature. But, thoughtemporary, such transients can have tremendous force and can do work orcause much damage and destruction if not properly controlled in thedesign and operation of pressure conduit systems.

For example, hydraulic transients, commonly known as “water hammer,” canoccur in a pressure conduit when confined liquid flow is slowed orstopped too quickly such as when rapidly closing a downstream valve. Therapid valve closure causes alternating high and low pressure waves andalternating reverse and forward flow until the “hammer” action is dampedout and stopped by friction or other means. The alternating pressurerise of this hammer action can be very powerful and has been commonlyknown to break pipelines and even blow buried pipelines entirely out ofthe ground.

An opposite type of hydraulic transient can occur downstream of arapidly closing valve where liquid is flowing away from the valve. Themass of the liquid flowing away from the valve creates a low pressure orsuction within the pipeline against the valve that has been known tocollapse and buckle pipelines.

Described herein is information known about how hydraulic transientsoccur, analysis of their general behavior, and explanation as to howcommonly known “ram pump” systems cause hydraulic transients to douseful work in pumping water. Known information about fluid moleculartheory and work processes are also briefly discussed. Also provided arenew insights and analyses of liquid transients and processes and howsuch can be controlled, manipulated, and harnessed in efficientprocesses that do useful work. Additionally, renewable energy cycleprocesses are provided that may renew or aid in renewing thethermodynamic properties of the operating liquid so that the liquid canbe recycled or re-circulated in a closed liquid system and continue tobe used to do useful work.

For convenience and simplicity only, as used herein, the term “water”represents any liquid and the term “pipeline” represents any pressureconduit. So, the term “water” as used herein means any liquid and theterms “pipe” or “pipeline” as used herein mean any pressure conduit orany conduit or vessel that confines liquid flow so that the liquidpressure is, or becomes, anything other than atmospheric pressure duringa hydraulic liquid transient.

Confined Liquid Transients/Water Hammer

Whenever the velocity of a confined liquid flowing in a pressurepipeline is increased or decreased, transient pressures result in theflowing liquid that travel up or down the pipeline at a speed thatmatches the speed of sound in the liquid in the pipeline since sound isitself a pressure wave in the liquid. These transient pressures areoften referred to as water hammer. It is commonly known that waterhammer occurs when a flowing liquid is stopped rapidly such as whenclosing a valve rapidly. The change in the momentum of the liquidmomentarily and cyclically creates elastic reactions in the liquid and aseries of alternating positive and negative pressure waves and liquidflows travel back and forth in the pipeline at the speed of sound themagnitude being reduced in each cycle by friction until eventually being“damped out” by the friction. Using Newton's Second Law, a commonlyaccepted and experimentally proven equation for computing the initialpressure rise in the pipeline at the valve for rapid valve closure isJoukowsky's equation expressed as:

P _(i) =ρ c _(p) v  (1)

Where

-   -   P_(i)=initial pressure rise    -   ρ=liquid density    -   c_(p)=the speed of sound in the liquid within the pipeline    -   v=initial velocity in the liquid

The well-known derivation of this equation is provided below. In EnglishUnits, P_(i) has units of pounds per square feet (lbs/ft²). Expressed infeet (ft) of pressure head or in pounds per square inch (psi), theequation is respectively:

$\begin{matrix}{{{P_{i{({f\; t})}} = {\frac{c_{p}v}{g}\mspace{14mu} {or}}},{P_{i{({psi})}} = {\frac{c_{p}v}{2.31g}\mspace{14mu} {where}}}}{g = {{acceleration}\mspace{14mu} {of}\mspace{14mu} {gravity}}}} & (2)\end{matrix}$

This initial transient pressure P_(i) begins a pressure wave thattravels rapidly back up the pipeline from the valve at speed c_(p)toward the liquid source as each upstream element of liquid is broughtto a stop. The speed c_(p) depends upon the bulk modulus of elasticityof the liquid and the thickness and rigidity (or bulk modulus ofelasticity) of the pipeline walls and can be measured, or can beestimated, using well-known equations not presented here. An additionalmuch smaller pressure rise P_(p) then builds at the valve as upstreamfriction progressively attenuates the initial pressure rise upstream andprogressively causes a residual upstream pressure and velocity toremain. That residual upstream pressure and velocity causes additionalcompression in the downstream liquid as each upstream liquid element isbrought to rest “packing” additional water into the pipeline against thevalve causing an additional and much smaller pressure rise, P_(p).

The initial transient pressure rise P_(i) and the packing pressure P_(p)are in addition to the original pressure at the valve prior to the valveclosure. So, the total pressure at the valve is:

P _(t) =P _(o) +P _(i) +P _(p)  (3)

where

-   -   P_(t)=the total pressure at the valve after closure;    -   P_(o)=the original pressure at the valve before closure

To illustrate, consider a simple pipeline system having a downstreamvalve initially discharging water from a reservoir connected to theupstream end of the pipeline. If the downstream valve is quickly closed,the initial pressure rise P_(i), as predicted by equations (1) or (2),immediately occurs in the small increment or element of water stopped bythe valve. The pressure rise is then transmitted upstream to the nextelement causing it to stop thus forming a pressure wave front travelingat speed c_(p) back up the pipeline in the opposite direction of theoriginal flow. Downstream of the wave front the liquid has stopped andincreased in pressure by the initial rise pressure rise P_(i) and thepipeline has expanded or stretched slightly. Upstream of the wave frontthe velocity and pressure of the liquid and the pipeline diameter remainunchanged with flow continuing toward the valve as before until thepressure wave front progressively stops the flow as it rapidly transmitsback up the pipeline.

As the wave front reaches the reservoir, the flow is momentarily stoppedin the entire pipeline, but because the pressure in the pipeline nowexceeds the pressure from the reservoir the liquid is not inequilibrium. This lack of equilibrium causes an over-reaction andreverse flow begins from the pipeline into the reservoir at essentiallythe original velocity, but in the opposite direction reduced slightly byfriction. This reverse flow causes a pressure relief wave to travel backdown the pipe toward the valve. The relief wave front pushes waterbackward up the pipeline toward the reservoir through expansion of thewater and contraction of the pipeline to its original size at the wavefront.

When the pressure relief wave front reaches the valve, the reservoirpressure minus the friction loss is momentarily restored in the entirepipeline. But, because the water is then flowing away from the valvetoward the reservoir, its inertia, or momentum, exerts a negativepressure against the valve dropping the pressure at the valve. This lowpressure at the valve, friction, and the pressure in the reservoir atthe other end in a short time stop the reverse flow toward thereservoir. But, because low pressure then exists at the valve, the flowreverses and flow toward the valve begins again driven by the reservoirpressure toward the valve. When that reservoir pressure and flow wavereaches the closed valve, the flow abruptly stops again, the pressureimmediately rises, and the cycle begins again.

This cyclic process is repeated until damped out by friction causing a“hammering” effect against the valve and the pipe walls. Each pressurecycle becomes smaller in amplitude due to friction. The oscillations ofprogressively decreasing pressure and flow continue over time untildamped out by friction.

So, equations (1), (2), and (3) predict the initial positive pressurerise for the first water hammer cycle resulting from a rapidly closedvalve. Thereafter, each succeeding pressure rise at the valve becomessmaller until entirely damped out by friction. The oscillating transientpressure waves travel very quickly up and down the pipeline at speedc_(p), which pressure wave speed matches the speed of sound in theliquid within the pipeline. The time required for one-half of the hammercycle is computed by the equation:

t _(c)=2L/c _(p)  (4)

Where

-   -   t_(c)=the wave travel time from the reservoir and back to the        valve    -   L=the pipeline length

The half cycle time t_(c), sometimes termed the characteristic time forthe conduit, is the time that a positive pressure is maintained at thevalve. If the valve closure time is faster than the half cycle time,then the maximum positive pressure rise as predicted by equations (1),(2), and (3) will occur. But, if the valve closure time is slower, oneor more returning negative pressure waves superimpose upon the positivewaves caused by the closing valve and the initial pressure rise becomessmaller. Thus, the slower the closure time for the valve, the lesser theinitial pressure rise so that a very slowly closing valve will causelittle pressure rise. But, in contrast, any valve closure time fasterthan the half cycle time t_(c) will cause the maximum positive pressurerise. So, the half cycle time t_(c), which depends on the pipelinelength L and the wave speed c_(p), can be termed the effective closuretime for the valve because any faster closure time than the half cycletime t will result in the same maximum positive pressure rise predictedby equations (1), (2), and (3).

But importantly, if the initial positive pressure increase issufficient, another important phenomenon will occur that interrupts thewater hammer cycle at the end of the first half cycle. If at time t_(c)the pressure at the valve tries to drop below vapor pressure when thefirst returning negative pressure wave returns to the valve, the watercolumn at the valve vaporizes and ruptures. This vaporization occursbecause liquids cannot sustain pressures below their vapor pressure andso turn to gaseous vapor. The resulting rupture of the column of waterin the pipeline is called column separation.

When column separation occurs, the flow into the reservoir will continueaway from the valve as near rigid body flow with only a small decreasein flow. The momentum of the water column flowing away from the valvecauses additional vaporization of water near the valve and the vaporcavity grows until the flow away from the valve is stopped by thefriction, the reservoir pressure, and the low pressure in the vaporcavity.

The slowing process for the water in the pipeline takes a much longertime because the water column acts as a near rigid body with momentumrather than as a pressure wave moving through the liquid. The action ismore of a surge of water moving toward the reservoir at slightly lessthan the original flow velocity rather than that of a pressure wavetraveling at the speed of sound.

When the near rigid body flow toward the reservoir slows and stops dueto the higher reservoir pressure, friction, and the lower vapor pressureat the valve, the flow reverses back toward the valve driven by thereservoir pressure and causes the vapor cavity to begin to collapse. Atthe instant the vapor cavity entirely collapses and disappears, another,but smaller, positive pressure transient is generated and the cyclerepeats itself until damped out by friction.

Confined Liquid Transients from Rapid Downstream Valve Opening

Confined liquid pressure transients also occur during the rapid openingof a downstream valve. As is well known, when a closed valve having anupstream pipeline filled with liquid is opened, the initial flowvelocity is predicted by Equations (1), (2) or (3) rearranged to predictflow velocity as follows using Equation (2):

$\begin{matrix}{v = \frac{P\mspace{14mu} g}{c_{p}}} & (5)\end{matrix}$

Where

-   -   v=initial flow velocity (ft/s)    -   P=initial pressure (ft)

A negative pressure wave from the flow at the valve and the accompanyingrelease of the pressure transmits up the pipeline to the source at speedc_(p). Downstream of the pressure wave, the flow is restored to thevelocity predicted by Equation (5) reduced by the friction in thesection of pipeline from the valve to the rapidly moving negativepressure wave. When the negative pressure wave reaches the reservoir,the flow into the pipeline nearly doubles at the entrance—one near fullincrement caused by the negative pressure resulting at the pipelineentrance and another near full increment caused by the positivereservoir pressure. This positive pressure wave and near doubled flowthen transmits back down the pipeline at the speed c_(p), with thepressure and flow damped slightly again by friction. When the positivepressure wave and near doubled flow reaches the open valve and exits,the increased exit flow again causes another but lesser negativepressure wave to transmit back up the pipeline. The process repeats withlesser and lesser flow increases until steady state flow is reached inthe pipeline. The flow rate stabilizes at steady state because thepipeline friction and entrance and exit energy losses exactly equal theavailable potential pressure energy.

Confined Liquid Transients from Rapid Change of Upstream Flow

Another type of commonly known confined liquid pressure transient occurswhen an upstream valve, rather than downstream valve, is rapidly closed.The mass and momentum of the liquid flowing away from the valve createsa low pressure or suction within the pipeline at the valve. The lowpressure progresses downstream as long as the liquid continues to flow.If the flow does not exit from the end of the pipeline, the forces offriction, downstream pressure (if any), and the upstream low pressurenear the valve eventually bring the flow to a stop.

But, as long as the downstream flow continues, the pressure continues todrop at the valve and progressively downstream until the pressure at thevalve reaches vapor pressure. At vapor pressure, the liquid vaporizes atthe valve and the liquid column ruptures. As the liquid continues toflow away from the valve, a vapor cavity forms at the valve andincreases in size progressing downstream as long as the liquid continuesto flow away from the valve. This action has been known to crumple andcollapse pipelines from the force of atmospheric pressure against thenear vacuum within the pipeline.

If the pipeline can withstand the outside atmospheric pressure forces,the vapor cavity that forms at the valve grows until eventually the flowis brought to a stop. The flow then reverses due to atmospheric pressureand downstream pressure (if any). The reverse flow collapses the vaporcavity causing a water hammer reaction in the pipeline that willcontinue until damped out by friction. But, in general, a low pressuretransient is constrained by the vapor pressure of the liquid.

Ram Pump Operation and Efficiency

Ram pump technology has been around since the late 1700's. A ram pumpuses transient confined liquid pressures to automatically pump water toa higher elevation using only the energy of flowing water. A typical rampump system comprises a drive pipeline leading from a water source, to apump unit having a waste valve and an outlet check valve leading to anair chamber and a pump discharge/outlet pipeline. The pump outletpipeline carries the pump pressurized water to its desired destinationat a much higher elevation than the water source. Various configurationsand constructions of waste valve, air chamber, and outlet pipeline havebeen found to work with some more efficient than others. But, eachbasically operates in similar manner in that water is introduced intothe drive pipeline from the water source at an elevation sufficientlyhigher than the waste valve to create velocity in the drive pipeline andwaste valve sufficient to cause the waste valve to alternately close andreopen.

The water flows from the source down the drive pipeline through aninitially open waste valve discharging water to any channel orconfiguration that can continuously accept the waste flow and convey itaway from the waste valve. As the velocity through the waste valveincreases, the drag forces of the increasing water flow through thevalve at some point result in rapid closure of the valve. The rapidclosure of the waste valve causes high transient pressures in the pumpunit and the drive pipeline which in turn causes the check valve leadingto the air chamber and pump outlet pipeline to open and let hightransient pressurized water into the air chamber. The water entering theair chamber through the check valve compresses the air in the chamberand causes water to flow up the outlet pipeline to discharge from thepipeline at an elevation much higher than that of the water source. Atsome point, the transient pressures at the waste valve and in the drivepipe reduce below the pressure in the air chamber and outlet pipelineand the check valve closes preventing reverse flow and maintaining thepressure in the air chamber and outlet pipeline. The closing of thecheck valve and remaining transient pressures in the pump body causes aback pressure surge transient to travel back up the drive pipeline tothe source. The back surge relieves the pressure at the waste valvecausing the waste valve to reopen and the flow in the pipeline thenreverses. Water begins again to discharge through the waste valve andthe cycle begins again.

Meanwhile, during the time of the back surge and subsequent waste flowin the drive pipeline of the next cycle, the check valve remains closedand the compressed air in the air chamber continues to push water up thedischarge pipeline until the pressure in the air chamber equalizes withthe water pressure elevation at the discharge pipeline outlet. The airchamber thus functions to even out the pumped flow by accepting andstoring water through compression of the air in the chamber during thetime of high transient pressures (pressures greater than the outletwater pressure elevation). Then as the transient pressures drop and thecheck valve closes, the air chamber pushes the temporarily stored waterup the outlet pipeline to its outlet during the time of lower pressuresin the drive pipeline and waste valve.

Ram pump cycle times can range from 30 to 100 cycles per minute and areoften most efficient in the range of 60 cycles per minute. Ram pumpsystem efficiency is commonly evaluated by dividing the pumped flow ratetimes its pumped elevation head by the total drive pipe flow rate(pumped flow plus waste flow) times the water source elevation head asfollows:

$\begin{matrix}{E_{p} = \frac{Q_{p}H_{p}}{\left( {Q_{p} + Q_{w}} \right)H_{s}}} & (6)\end{matrix}$

Where

-   -   E_(p)=Ram pump system power efficiency    -   Q_(p)=Pumped water flow rate    -   Q_(w)=Wasted water flow rate    -   H_(p)=Pumped water elevation head    -   H_(s)=Source water elevation head

This power efficiency E_(p) can range from 0 to above 0.85 (0 to above85 percent), depending upon the overall design of the system withtypical efficiencies in the range of 0.60 (60 percent efficient). Thatmeans that 60 percent of the power of the water entering the drivepipeline from the water source is transferred to, and maintained in, thepower of the pumped flow while 40 percent of the power is lost in thedischarge of the waste flow. Ram pump volumetric efficiency is commonlycomputed as follows:

$\begin{matrix}{E_{vol} = \frac{Q_{p}}{\left( {Q_{p} + Q_{w}} \right)}} & (7)\end{matrix}$

Where

-   -   E_(vol)=Ram pump volumetric efficiency    -   Q_(p)=Pumped water flow rate    -   Q_(W)=Wasted water flow rate

The volumetric efficiency is often quite poor ranging as low as 0.05 to0.10 (5 to 10 percent pumped flow versus 90 to 95 percent wasted flow).Due to the large waste flow compared to the flow of the water pumped,ram pumps are not practical in many applications. But, where water flowis abundant with only the need of pumping a minor percentage of thesource water, ram pumps have proven to reliably provide pumped water formore than 50 years of operation.

Going back to the commonly accepted method of computing ram pumpefficiency expressed in Equation (6), the method is actually rathercurious in that it evaluates the overall power efficiency of the entiresystem (the ram pump with its upstream and downstream pipelines) ratherthan the power efficiency of only the ram pump itself. In contrast,evaluation of the power efficiency of turbines focuses solely on theefficiency of the turbine unit itself in converting water pressure andflow energy into mechanical energy. If the turbine drives a pump, thenthe efficiency analysis of the combined turbine-pump unit focuses solelyon the efficiencies of the two units working together in transferringand imparting the energy of the flow entering the turbine to the energyof the pumped water discharging from the pump. The overall systemfriction caused power losses of getting flowing water to the turbine inthe upstream penstock pipeline and of conveying water downstream awayfrom the turbine in the downstream discharge pipeline are entirelyneglected in the efficiency evaluation because they really have nothingto do with the efficiency of the turbine unit or the combinationturbine-pump unit themselves.

But, with a ram pump a problem is presented. During the actual pumpingpart of the cycle (the pumping period), there is only a very small lossin the energy of the flowing water as it exits the drive pipeline andpump body through the check valve into the air chamber and dischargepipeline while there is a large energy gain in pressure and elevation ofthe pumped water. So, the energy efficiency of the pump itself duringthe actual pumping period is over 100 percent because all of the flowentering and exiting the pump during the pumping period of the cycle isbeing pumped. During the pumping part of the cycle only, the powerefficiency equation becomes:

$\begin{matrix}{E_{a} = {\frac{Q_{p}\mspace{14mu} H_{p}}{Q_{p}\mspace{14mu} H_{s}} = \frac{H_{p}}{H_{s}}}} & (8)\end{matrix}$

Where

-   -   E_(a)=Actual ram pump power efficiency    -   Q_(p)=Pumped water flow rate    -   H_(p)=Pumped water elevation head    -   H_(s)=Source water elevation head

Since, during the actual pumping period, the only water flow through theram pump is the pumped water Q_(p), Q_(p) appears both in the numeratorand denominator and the equation reduces to E_(a)=H_(p)/H_(s). SinceH_(p) is always greater than H_(s) for a functioning ram pump, the pumpefficiency during the actual pumping period only is always greater than1.0 or 100 percent.

Additional information and analysis of ram pump operation and additionalbackground in the physics of fluids is provided hereinafter.

Fluid Molecular Behavior

Well accepted and verified molecular theory of fluids (gases andliquids) is provided herein. It is well accepted that the molecules of agas have kinetic energy that causes the molecules to continually andrandomly move about, and that this molecular movement is ofteninfluenced by other forces such as gravity, molecular attractions, andcollisions with other molecules and objects in the path of theirtrajectory. This molecular kinetic energy is part of the internalthermal energy of the gas. The greater the internal thermal energy, thegreater the molecular kinetic energy. Conversely, the lesser theinternal thermal energy, the lesser the molecular kinetic energy of thegas.

On earth, atmospheric pressure is exerted on everything exposed to theatmosphere and is caused by the weight of the air column above(surrounding) the earth and by the energy of the collisions of the airmolecules with things on earth. When a gas is placed into a closedcontainer, the kinetic movement of the gas molecules causes the gasmolecules to fill the container and to collide with the container walls.The sum of these numerous collisions exerts a force, termed pressure, onthe inside of the walls of the container and on the molecules andanything else inside the container itself. When that pressure is equalto atmospheric pressure, the pressure forces on the outside of thecontainer and the pressure forces inside of the container are the same.

If the gas in the container is heated, the kinetic energy of the gasmolecules increases thereby increasing the force of the collisions ofthe gas molecules against the container walls and the other gasmolecules in the container, that is, the pressure within the containerincreases. Because, the pressure force against the inside of thecontainer walls becomes greater than the atmospheric pressure on theoutside of the container walls, strain is caused in the container walls.If the walls are sufficiently flexible, the walls of the container willexpand. Conversely, if a gas in a closed container initially atatmospheric pressure is cooled, the opposite reaction occurs. Thekinetic energy of the molecules decreases causing lesser collisionforces so pressure decreases and the walls of the container maycontract.

Going back to the gas in a container at atmospheric pressure, if a forceabove atmospheric pressure is exerted against a container wall such thatthe size of the container, or of the container space confining the gas,is decreased, the kinetic energy of the gas molecules causes increasingand more forceful molecular collisions against the container walls andthe pressure force within and against the container walls thusincreases.

In contrast, the behavior of liquids has both important similarities andimportant differences from that of gases. It is well known that unlikegases, the molecular attractions between liquid molecules becomesufficiently important to constrain the kinetic movement of liquidmolecules to a defined space. That defined space is the volume of theliquid at equilibrium and is determined by the molecular makeup of theliquid itself and by the internal energy content of the liquid. Likegases, when internal thermal energy content decreases, the volume of aliquid decreases, and when internal energy increases, the volume of theliquid increases, though molecular forces between the liquid moleculesconsiderably constrain the increases and decreases. Also like gases,part of the internal thermal energy content of liquids is comprised ofmolecular kinetic energy that causes the liquid molecules to continuallymove about and collide with each other and the walls of their container.Their movements are simply restrained by the attractions of the liquidmolecules to each other so that each molecule moves randomly in arelatively narrow space. But, it is the molecular collision forces, thesum of which contributes to liquid pressure, that are important inunderstanding the behavior of transient pressures in confined liquids.

Finally, unlike gases, it is well known that liquids are not easilycompressed because the internal energy forces of the molecules within aliquid very strongly resist compression. For example, the bulk modulusof elasticity for water is 305,000 pounds per square inch (psi) at 50°F. That means that a 30.5 psi pressure change in water, which isequivalent to 70.5 feet of water pressure head, produces only a one tenthousandth (0.0001) change in volume and 705 feet of water pressure headproduces only a one thousandth (0.001) change in volume.

So, in unconfined water flow and non-transient confined flow, waterbehaves essentially as an incompressible fluid so that the physics ofmost water flow and water power conditions can be acceptably analyzedassuming water to be incompressible. However, when transient pressuresare caused in confined flow in a pipeline or pressure conduit, thebehavior of water and other liquids becomes like that of compressiblefluids and the physics of compressible fluids must be applied. But, itmust be remembered that for liquids, the equilibrium between themolecular attractions and the internal energy of the fluid moleculesrequires that a liquid must occupy a certain volume of space, no moreand no less. If that volume is less, then the pressure and reaction ofinternal forces increase accordingly.

Fluid Transient Work Processes

Gas transient work processes involve changes in the volume and pressureof a gas in a confined space. It is well accepted that the amount ofwork that is done by a particular process involving a gas depends on howthe pressure and volume are allowed to change in the process. Animportant example process can be illustrated by considering a closed andcompletely insulated container divided into a lower chamber and upperchamber by a rigid membrane having gas in the lower chamber and acompletely empty space under vacuum in the upper chamber. If themembrane is somehow removed or broken without opening the container, thekinetic energy of the gas molecules will cause the gas to rapidly expandfrom the lower chamber to entirely fill both chambers. A lower pressurewill result because the molecules will have more space within which tomove. Most importantly in this case, the gas does no work because noforce is required for the gas to expand into the vacuum.

On the other hand, it is well known that work can be done by the samegas in the lower chamber as it expands into the space of the upperchamber if the process is changed and configured correctly. The membranecan be replaced by a moveable piston sealed against the walls of thecontainer with the upper chamber open to the atmosphere and exactlyenough weight on the piston to hold it down against the pressure of thegas in the lower chamber. When most of the weight is removed from thepiston, the lower chamber pressure, resulting from the kinetic energy ofthe collisions of the gas molecules against the bottom of the piston,causes the piston and the remaining weight upon the piston to rise whilethe gas expands beneath the piston into the space of the upper chamber.In so doing, the expanding gas does work upon the piston and remainingweight by causing them to move a distance upward through most of thespace of the upper chamber. In this case, work is done because thepressure force of the gas in the lower chamber pushes the piston andremaining weight a distance upward.

Similarly, the moment a confined liquid under transient pressure isallowed to expand into an empty space such, as the upper chamber, theliquid molecules simply use more space in their random kineticmovements. The difference is that, if the empty space is larger thanneeded for equilibrium, other internal molecular forces within theliquid constrain the liquid molecules to the volume or space thatresults in molecular equilibrium. So, the liquid only expands to isequilibrium volume which volume may not fill the upper chamber space.Further, as with the gas, the liquid does no work in that naturalexpansion to its equilibrium volume. The liquid simply expands to itsequilibrium volume filling only that volume of empty space that isneeded for that volume. Part of the liquid may vaporize because pressureis initially below vapor pressure, but no work is done.

If the empty space is replaced with air open to the atmosphere, theexpansion of the liquid does a very small amount of work in pushing airaway as it expands to its equilibrium volume, but little to no usefulwork is done. Finally, if the empty space is replaced with air either atatmospheric pressure or above but confined in an air tight container,the expansion of the liquid into the space occupied by the air does onlythe amount of work needed to compress the air and allow the liquid toexpand to its equilibrium volume. The result is air slightly compressedabove the initial air pressure in the chamber, which can be useful as inthe typical ram pump design, but again most of the liquid transientpressure is relieved without doing work.

As is discussed hereinafter, these two fluid processes, one that doeswork through expansion and one that does not, are useful inunderstanding and explaining the behavior of liquid fluid transients andhow to make those transients efficiently do work.

Work and Heat

Well accepted laws of thermodynamics hold that energy is never creatednor destroyed, but that energy can be transferred between molecules ofmatter through either the processes of work or heat. Work is defined inphysics as the process of moving a mass of any substance over adistance. In accomplishing that process, energy is transferred to orfrom the mass moved and work can thereby transfer energy in or out of asystem.

Heat is also an energy transfer process that operates when two bodies ofmass that are at different temperatures, hence at different energystates, are in close enough proximity to each other to cause energytransfer. Through the process of heat, the energy from the mass ofhigher temperature and thus, higher internal energy, transfers to themass of lower temperature and internal energy. Because, as recognized bythe verified laws of thermodynamics, the heat process can only operateto transfer energy from a state of higher energy to a state of lowerenergy, the heat process continues only until the temperatures of thetwo masses equalize. At that point, the heat process ends.

The important principle here is that both the work and heat processescan act to increase or decrease the internal thermal and kinetic energyof a mass.

Other Principles and Information

Other principles, formulae, and information include:

1. The full energy equation for a flowing liquid expressed in dimensionsof energy per unit mass is:

$\begin{matrix}{{u_{1} + \frac{P_{1}}{\rho_{1}} + \frac{v_{1}^{2}}{2} + {{gz}_{1} \pm E_{m}} + E_{H}} = {u_{2} + \frac{P_{2}}{\rho_{2}} + \frac{v_{2}^{2}}{2} + {gz}_{2}}} & (9)\end{matrix}$

Where:

-   -   u₁=initial non-pressure internal energy    -   u₂=final non-pressure internal energy    -   P₁=initial pressure    -   P₂=final pressure    -   ρ₁=initial liquid density    -   ρ₂=final li quid density    -   P₁/ρ₁=initial pressure energy    -   P₂/ρ₂=final pressure energy    -   v₁=initial velocity    -   v₂=final velocity    -   v₁ ²/2=initial kinetic energy    -   v₂ ²/2=final kinetic energy    -   g=acceleration of gravity    -   z₁=initial elevation    -   z₂=final elevation    -   gz₁=initial potential gravity energy    -   gz₂=final potential gravity energy    -   E_(m)=energy entering or leaving the system as mechanical work    -   E_(H)=energy entering or leaving the system as heat flow        (including friction loss)

2. The kinetic energy quantity v₁ ²/2 converts to v₁ ²/2 g(g=acceleration of gravity) when the units are in feet of water commonlyreferred to as “head.”

3. The pressure force F is equal to PA (F=PA) where P=pressure andA=Area on which the pressure acts. Also, flow rate Q is equal to Av(Q=Av) or flow area times velocity.

4. The well-known momentum equation for steady incompressible liquidflow is:

F ₁ −F ₂ =ρQv ₂ −ρQv ₁ =ρQ(v ₂ −v ₁)  (10)

where:

-   -   F₁=initial pressure force against the flow volume    -   F₂=final pressure force against the flow volume    -   Q=flow rate    -   ρ=liquid density    -   v₁=initial velocity vector    -   v₂=final velocity vector    -   ρQv=the momentum flux

The quantity ρQv is known as the momentum flux which is the momentumforce of the liquid. Now consider a free body diagram of a short liquidelement in a flowing pipeline located immediately upstream of a valve.At steady incompressible flow, the forces are as follows:

F₁ is the pressure force on the element driving the flow. The quantityρQv is the momentum flux of the element of flowing liquid, F₂ is thedownstream force on the element opposing the flow, and force F₁comprised of downstream friction and pressure forces. Because theelement is short, the friction force is very small and can be neglectedor lumped in with force F₂ opposing the flow. Summing the forces for theflowing liquid yields:

F ₂ =ρQv+F ₁ or F ₂ −F ₁ =ρQv

So, the difference between the two forces acting on the short liquidelement, F₂−F₁, is equal to the momentum flux ρQv. Now consider whatforce it would take to instantaneously stop the liquid flow. Theresisting force would need to be sufficient to resist both the drivingforce F₁ and the momentum flux force, ρQv. As shown here, ρQv is equalto F₂−F₁. So, that much additional force (F₂−F_(i)) is needed toovercome the momentum flux. The free body diagram of the forces forinstantaneously stopping the flow is as follows:

Summing the forces, the equation for stopping the liquid underincompressible conditions yields:

F ₁ +ρQv=F ₂+(F ₂ −F ₁) or 2(F ₂ −F ₁)=ρQv

Remembering F=PA where P=pressure and A=Area on which the pressure acts,and that Q=Av, the equation becomes:

${{P_{2}A} - {P_{1}A}} = \frac{\rho \; {Av}^{2}}{2}$

which simplifies to:

$P_{2} = {P_{1} + \frac{\rho \; v^{2}}{2}}$

Thus, for incompressible liquid flow, the final pressure P₂, is equal tothe initial pressure P₁ plus the quantity ρv²/2 and the change inpressure, P₂−P₁, is thus equal to ρv²/2; or, in units of head or feet ofwater, is equal to v²/2 g. That quantity, ρv²/2 or v²/2 g, is thekinetic energy of the liquid in the energy equation.

5. For compressible liquid flow, it is well accepted and verified thatthe effect of rapid changes in liquid momentum cannot be analyzedassuming incompressible flow, but must be analyzed using themomentum-impulse equation of Newton's second law:

F dt=m dv

where

-   -   F=force applied to change the momentum    -   dt=time the force is applied    -   m=mass of the liquid    -   dv=change in velocity of the liquid

If a confined liquid in a pipe is stopped instantaneously, it has beendetermined that a pressure wave travels up the pipe at the velocity of apressure wave within the pipeline liquid c_(p), which velocity is alsothe speed of sound within the pipeline liquid. That pressure wave isformed in a short interval of time, dt, as an element of liquid oflength, c_(p) dt, comes to rest. Applying Newton's Law while neglectingfriction:

F dt=m dv; Or, −A dp dt=ρA c _(p) dt dv

which simplifies to: −dp=ρ c _(p) dv

Since velocity is reduced to zero, dv=−v and dp is the resultingpressure transient, upon integration the equation for the initialtransient pressure becomes:

P _(i) =ρ c _(p) v which is equation (1) above.

Thus, application of impulse momentum principles yields equations (1)and (2) above for an initially flowing liquid. So, for any point ofinterest in the upstream pressure conduit, the pressure rise P_(i) asthe wave reaches that point can, neglecting friction, be evaluated fromthe impulse momentum equation F t=m v, P_(i) A t=m v, or P_(i)=m v/A t;where A is the conduit area, time t is equal to the length (L) of theupstream pressure conduit to the point of interest divided by the speedof the pressure wave c_(p), or t=L/c_(p), and the mass (m) is that massof the liquid in the conduit from the point of change to the point ofinterest (the liquid mass affected by the change to the point ofinterest).

6. In a flowing liquid, the fluid molecules are the mass of the liquidand each molecule individually has inertia or momentum, while thecollective effect of that individual molecular inertia or momentum isexhibited in the behavior of the liquid as a whole.

7. The wave speed, c_(p) is directly related to the rigidity orflexibility of the pipeline. The more rigid the pipeline, the greaterthe pressure wave speed c_(p) and the greater the transient pressurerise, and conversely, the more flexible the pipeline, the lesser thewave speed and the lesser the transient pressure rise. A representativegalvanized steel pipeline pressure wave speed, c_(p), is about 4,590feet per second.

8. Devices that relieve and dissipate transient pressures have beenknown and in use for a long time. They each work under the same basicprinciple—relieve the confinement of the liquid and the excess pressuredissipates.

9. The second law of thermodynamics requires that there must be anenergy loss from liquid entering and flowing in a pipeline, not anenergy gain.

10. Transient pressure waves, or wave pulses, traveling in liquidsconfined in a conduit are affected by changes and discontinuities in theconduit such as diameter or area changes, junctions or tees, dead-endsor closed valves, exits and entrances to tanks, reservoirs, pressuredissipation devices, and the like. When a transient wave pulse reachessuch discontinuities the wave pulse reflects back and/or transmitsthrough the change or discontinuity as a new set of one or more wavepulses. Except most conduit bends cause relatively minor disturbance tothe transmittal of transient wave pulses so that they can be usuallytreated as friction losses, but transient wave pulses are neverthelessdisturbed wherever flow velocity changes occur.

Importantly, at diameter or area changes, the instant a wave pulse of aparticular pressure reaches the diameter or area change, a new wavepulse reflects back at a different pressure and travels back up theconduit in the opposite direction while a new wave pulse transmits at adifferent pressure through the diameter or area change and continuestraveling down the conduit in the same direction as the original wavepulse. The new reflected and transmitted wave pulse pressures arecomputed applying the principles of mass and linear momentumconservation in the following equations:

${\Delta \; P_{t}} = {{\frac{2\; c_{p\; 1}A_{2}}{{c_{p\; 2}A_{1}} + {c_{p\; 1}A_{2}}}\Delta \; P_{o}\mspace{14mu} {and}\mspace{14mu} \Delta \; P_{r}} = {{\Delta \; P_{o}} - {\Delta \; P_{t}}}}$

Where

-   -   ΔP_(o)=Original incoming wave pulse pressure    -   ΔP_(r)=Reflected wave pulse pressure    -   ΔP_(t)=Transmitted wave pulse pressure    -   A₁=Upstream conduit area    -   c_(p1)=Upstream conduit wave speed    -   A₂=Downstream conduit area    -   c_(p2)=Downstream conduit wave speed

If the wave speeds are the same upstream and downstream the wave speedterms may be dropped from the equation so that the equations become:

${\Delta \; P_{t}} = {{\frac{2\; A_{2}}{A_{1} + A_{2}}\Delta \; P_{o}\mspace{14mu} {and}\mspace{14mu} \Delta \; P_{r}} = {{\Delta \; P_{o}} - {\Delta \; P_{t}}}}$

Increases in downstream pipe diameter or conduit area, or decreases inwave speed cause a decrease in the magnitude of the wave pulse pressuretransmitted downstream and an increase in the magnitude of the wavepulse pressure reflected back upstream. The opposite is true for adownstream pipe diameter or conduit area decrease or wave speedincrease. An increased pressure wave pulse is transmitted downstream anda decreased pressure wave is reflected upstream.

Similarly, at junctions or tees, a new wave pulse reflects back up theupstream conduit and new wave pulses are transmitted down the downstreamconduits with pressures computed by applying the principles of mass andlinear momentum conservation as follows:

${\Delta \; P\; 1_{r}} = {{\Delta \; P\; 2_{t}} = {{\Delta \; P\; 3_{t}} = {\frac{2\; c_{p\; 1}c_{p\; 2}A_{3}}{{c_{p\; 2}A_{1}} + {c_{p\; 1}A_{2}} + {c_{p\; 3}A_{3}}}\Delta \; P_{o}}}}$

Where

-   -   ΔP_(o)=Original incoming wave pulse pressure traveling in        incoming conduit 1    -   ΔP1_(r)=Reflected wave pulse pressure back up incoming conduit 1    -   A₁=Incoming conduit 1 area    -   c_(p1)=Incoming conduit 1 wave speed    -   ΔP2_(t)=Transmitted wave pulse pressure in downstream conduit 2    -   A₂=Downstream conduit 2 area    -   c_(p2)=Downstream conduit 2 wave speed    -   ΔP3_(t)=Transmitted wave pulse pressure in downstream conduit 3    -   A₃=Downstream conduit 3 area    -   c_(p3)=Downstream conduit 3 wave speed

Again, if the wave speeds are the same upstream and downstream the wavespeed terms may be dropped from the equation. Changes in diameter andwave speed at the tees or junctions have the same effect as describedabove for changes in diameter and wave speed at any other pipe orconduit diameter or area change.

At dead ends and closed valves, the wave pulse reflects back upstream asa new wave pulse at a pressure double to that of the original incomingwave pulse. This occurs because the incoming wave pulse induces avelocity in the conduit toward the dead-end. That velocity then causes afurther and double compression of the liquid at the dead-end resultingin the reflection of a new wave at double the incoming wave pulsepressure. The doubled pressure then travels as a wave pulse in thereverse direction back up the conduit away from the dead-end.

Transient Pressure Energy Processes

The process of water hammer as well as the operation of ram pumps asexplained above is instructive as to what actually happens in theseprocesses and why. First of all, in water hammer, the transient pressurewave returning to the liquid source has more total energy than thepotential energy of the source that provided it on the first return ofthe positive transient pressure wave back to the liquid source.

At the instant the transient pressure wave from the rapidly closed valvereaches the reservoir the flow in the pipeline has completely stopped.For an instant before the flow reverses and water flows back into thereservoir, the water in the pipeline is at a much higher pressure andthus higher potential energy than it originally started with when thewater originally entered the pipeline from the reservoir. Then becausethe pressure is higher, the flow reverses and water flows under thehigher pressure and potential energy back into the reservoir.

The following provides analysis, basic theory, and design principles toavoid dissipation of confined liquid transient pressure energy and toharness and replenish this energy in energy cycles, and presents anddiscusses confined liquid transient pressure work processes.

Liquid Transient Theory and Analysis

1. The Role of Molecular Momentum

It is known that the transient pressure increase is immediate at thevalve as the liquid comes to a stop. It is also known that the pressureincrease is directly related to the momentum of the liquid since theaccepted and verified equations (1) and (2) above are derived usingmomentum analysis. It is also known that at the instant of the pressureincrease that forms and begins the pressure wave front in the liquidimmediately upstream of the valve, the liquid upstream of the pressurewave front has not yet come to a stop. Each of these known principlesare discussed hereinabove.

Thus, it is known that the immediate pressure increase in the liquid atthe valve is caused by an impulse force applied against the momentum ofthe liquid, but that this immediate rise is not caused by the momentumof the upstream liquid column. But rather, it is known that the pressureincrease is caused by the elastic reaction of the liquid at the pressurewave front.

That means that the immediate pressure rise at the wave front is notcaused by collisions with the upstream water column, but rather only bycollisions with the downstream water column. So, the high pressureimpulse caused by a closing valve is not, and cannot be, caused by anypart of the water column upstream of the pressure wave front because theliquid upstream of the wave front has not yet received any effect of theclosing of the valve. Rather, the upstream liquid still flows as if novalve closure had occurred. So, the initial pressure increase at thevalve, and at the wave front as it travels back up the pipeline, mustresult from an elastic momentum effect on the liquid.

The key to understanding how to harness transient pressure energy to douseful work is found in an analysis of the momentum impulse effect onthe individual liquid molecules themselves.

As discussed above, the equilibrium between the molecular attractionsand the internal energy of the liquid molecules requires that liquidmust occupy a certain volume of space, no more and no less. If thevolume is caused to be less, molecular collision and other internalforces immediately oppose the volume decrease. The molecules exertpressure against each other and against their container until relievedthrough expansion back to the equilibrium volume as determined by thebalance between the amount of internal energy and the molecularattractions and other forces within the liquid.

In a flowing liquid, the individual molecules themselves are the mass ofthe liquid and therefore are what have inertia and momentum, thecollective effect of which is seen in the behavior of the liquid as awhole. As a valve in a pipeline rapidly closes, the volume equilibriumof the liquid is disrupted as the inertia of the individual liquidmolecules causes the molecules to pack closer together creatingincreased collision forces, and thus increased pressure within theliquid and against the pipeline walls. So, it is the inertia causedpacking or compression of the liquid molecules together that causes theimmediate pressure rise at the valve and pressure wave front.

2. Energy Equation and Momentum Analysis

The theory that it is the internal molecular energy within a liquid thatcauses the immediate pressure rise at a rapidly closed valve and at thepressure wave front as it transmits upstream in the pipeline can beevaluated using the well-known general energy equation for fluids. Thefull energy equation for a flowing fluid expressed in dimensions ofenergy per unit mass is:

$\begin{matrix}{{u_{1} + \frac{{P\;}_{1}}{\rho_{1}} + \frac{v_{1}^{2}}{2} + {{{gz}_{1} \pm E_{m}} \pm E_{H}}} = {u_{2} + \frac{P_{2}}{\rho_{2}} + \frac{v_{2}^{2}}{2} + {gz}_{2}}} & (11)\end{matrix}$

Where:

-   -   u₁=initial unavailable internal energy    -   u₂=final unavailable internal energy    -   P₁=initial pressure    -   P₂=final pressure    -   ρ₁=initial liquid density    -   ρ₂=final liquid density    -   P₁/ρ₁=initial pressure energy    -   P₂/ρ₂=final pressure energy    -   v₁=initial velocity    -   v₂=final velocity    -   v₁ ²/2=initial kinetic energy    -   v₂ ²/2=final kinetic energy    -   g=acceleration of gravity    -   z₁=initial elevation    -   z₂=final elevation    -   gz₁=initial potential gravity energy    -   gz₂=final potential gravity energy    -   E_(m)=energy entering or leaving the system as mechanical work    -   E_(H)=energy entering or leaving the system as heat flow        (including friction loss)

The quantities u₁ and u₂ represent the internal energy unavailable to dowork. Applying that equation to an initial condition of a liquid flowingby gravity in a steel pipeline through a downstream valve and a finalcondition of stopped liquid at the valve after rapid closure to evaluatethe immediate transient pressure rise caused by the rapidly closingvalve, it can be assumed or deduced that: (1) because of the rapidclosure, the process is adiabatic—meaning no heat has time to exit orenter the system, (2) the final velocity v₂ is zero, and (3) the z₁ andz₂ terms can be ignored (by assuming for convenience that the pipelineand valve system are horizontal). The equation thereby reduces to:

${u_{1} + \frac{{P\;}_{1}}{\rho_{1}} + {\frac{v_{1}^{2}}{2} \pm E_{m}}} = {u_{2} + \frac{P_{2}}{\rho_{2}}}$

Depending on how it is accomplished, rapid closure of a valve canrequire very little mechanical energy, or, can be accomplished by theflow of the liquid itself as in the instance of a ram pump waste valve,which easily closes from the kinetic drag forces of the flowing liquid.So, the work energy addition to the system in closing the valve iseither zero (in the case or a ram pump) or very small (for mostmechanically operated valves) and can be neglected and dropped from theequation as zero or negligible in assessing the cause of the pressureenergy rise, P₂.

Further, recognizing that v₁ ²/2 converts to v₁ ²/2 g (g=acceleration ofgravity) when the units are in feet of water commonly referred to as“head”, the gravity caused quantity v₁ ²/2 g can be shown to be verysmall as compared to the pressure rise, P₂ that occurs upon the rapidclosure of the valve and the rapid stopping of the liquid flow. Forexample, if the initial velocity v₁ is equal to 1, 10, or 15 feet persecond, the velocity head v₁ ²/2 g is equal to 0.015, 1.55, and 3.49feet of head respectively. While applying equation (2) in units of feetof head and using a reasonably representative steel pipeline pressurewave speed, c_(p), of about 4,590 feet per second, the resultingpressure P₂ calculates to be 142.5, 1,425, and 2,138 feet of headrespectively. Thus, since the velocity head caused by gravity representsonly about a hundredth or thousandth or less of the pressure energy riseof P₂, the initial velocity head term v₁ ²/2 can also be neglected asinsignificant in assessing the cause of the pressure energy rise P₂, andthe equation simplifies to:

$\begin{matrix}{{u_{1} + \frac{P_{1}}{\rho_{1}}} = {u_{2} + \frac{P_{2}}{\rho_{2}}}} & (12)\end{matrix}$

or, rearranged:

${\frac{P_{2}}{\rho_{2}} - \frac{P_{1}}{\rho_{1}}} = {u_{1} - u_{2}}$

Thus, the change in pressure energy (P₂/ρ₂−P₁/ρ₁) is essentially equalto the change in unavailable internal energy (u₁−u₂). The change in theunavailable internal energy (u₁−u₂) results from the immediate inertialforce caused compression or packing of the liquid molecules closertogether. That molecular compression or packing concentrates theinternal energy of the liquid into a smaller space upsetting themolecular equilibrium and resulting in the conversion of a part of thenormally unusable non-pressure internal energy of u₁ into usableinternal pressure energy, P₂. The large pressure increase (P₂−P₁) in thestopped liquid thus results from the increased molecular collisionshappening between other liquid molecules and against the pipeline walls.In other words, the non-pressure internal energy of u₁ decreases to thatof u₂ while the pressure energy P₁/ρ₁ increases in essentially a likeamount to the pressure energy of P₂/ρ₂.

Thus, the conclusion can be made, based on the above analysis applyingthe energy equation to the rapid closure of a valve, that the immediatelarge transient pressure rise caused by the rapid closing of the valvemust derive in large measure from the inertia caused change in theunavailable internal energy content of the liquid. The large pressurerise is not, and cannot possibly be, due to the decrease in the kineticenergy of the uncompressed flowing water, v₁ ²/2, which as has beenshown, is but a small and insignificant fraction of the total pressurerise that occurs. Rather, it is the small volume decrease and smalldensity increase in the liquid that upsets the molecular equilibrium ofthe liquid and causes powerful internal molecular energy forces to reactand increase the liquid pressure. Thus, the theory does indeed appear tobe correct that the inertia caused immediate compression or packing ofthe liquid molecules closer together causes the immediate pressure riseat the valve and at the pressure wave front.

That conclusion can be checked with the incompressible liquid momentumequation. An analysis of that equation applied to an incompressiblefluid is provided herein (see Other Principles and Information). Thatanalysis shows that the incompressible momentum of the liquid isequivalent to the gravity caused kinetic energy of the liquid and thatthe predicted change in pressure resulting from the momentum of theliquid is equal to the gravity caused kinetic energy quantity v²/2 gexpressed in units of head or feet of water. So, the gravity causedkinetic energy of the liquid, v²/2 g, is the entire quantity of liquidmass momentum energy available for the pressure rise P₂−P_(i). And asshown above, for velocities of 1, 10, and 15 feet per second, and so on,that kinetic energy of 0.015, 1.55, and 3.49 feet of head respectively,is far less than the pressure energy that actually results from rapidstopping the flow, which for a steel pipe with c_(p)=4,590 feet/second,is 142.5, 1,425, and 2,138 feet of head respectively, and so on. Onlywhen liquid molecular theory and the impulse-momentum equations ofcompressible flow are used, can one properly analyze and compute thepressure increases that actually occur in the rapid stopping of liquidflow.

Thus, based on both energy analysis and momentum analysis, the energy inthe large initial pressure rise P₂ of a liquid that occurs upon theinstantaneous or rapid stopping of a fluid flow, cannot possibly derivefrom the momentum or kinetic energy of the upstream liquid in itsuncompressed state. The momentum energy of the uncompressed liquid byitself simply does not have the power to cause the compression of thedownstream liquid. Rather, the inertial forces acting on the liquidmolecules themselves must be concluded to be the major cause of thecompression of the liquid that in turn results in the large pressureenergy rise. In actuality, the inertial or momentum force causedcompression of the liquid creates an internal molecular force imbalancein the liquid, and internal energy is converted to pressure energy.

In sum, in the rapid stopping or slowing of a liquid, part of thenormally unusable internal molecular energy of the liquid is convertedto usable pressure energy. That is a phenomenon of great importance. Aprocess has been found that converts internal molecular energy inliquids into pressure energy. That process is dependent upon thevelocity and momentum of the liquid molecules themselves immediatelybefore stopping or slowing. That velocity and momentum or inertia is notdependent upon the energy lost in the waste flow, but rather isdependent upon the pressure and wave speed as expressed by Equation (5).

So, what is needed now is to improve the efficiency of the initiationand recovery of flow after rapid stoppage or slowing so that moreinternal energy is converted to pressure energy than is lost in the flowrecovery process and a new energy source, liquid thermal internalenergy, is available for use. How to accomplish that improvement forboth the transient pressure work process and the flow recovery processis discussed below.

Dissipation of Confined Liquid Transient Pressure Energy

To improve work process energy efficiencies, it is important to firstunderstand what relieves confined liquid transient pressures withoutdoing work. Devices that relieve and dissipate transient pressures havebeen known and in use for a long time. They each work under the samebasic principle—allow the liquid to expand into a larger space and theexcess pressure dissipates. Understanding how and why that actuallyworks is important to the design of systems intended to harness, ratherthan dissipate, transient pressure energy.

As a gas or a liquid that expands into and fills an empty containerchamber, the gas or liquid does no work because no force is required forthe gas or liquid to expand into the empty chamber. Rather, the gas orliquid molecules simply use more space in their random kinetic movementscaused by the internal energy of the gas or liquid. For a liquid, thatspace is constrained by the equilibrium between the attraction forcesbetween liquid molecules and the kinetic movements of the liquidmolecules. The liquid simply expands to its equilibrium volume fillingonly that volume of empty space that is needed for that volume.

So, similar to a gas, the manner and process by which a transient liquidpressure is relieved significantly affects and determines the amount ofwork that is done while relieving that transient pressure. The work donedepends on how the pressure and volume of the liquid are allowed tochange through the process. Only the exact amount of work is done thatis necessary to achieve the expansion of the liquid to its equilibriumvolume, no more and no less. The work potential of any transientpressure energy in excess of that needed for the expansion is simplydissipated by transforming the pressure energy back into internal energywithout doing work.

That phenomenon explains why increases in downstream pipe diameter orpipeline junctions with outgoing pipelines of the same or greaterdiameters always cause reduction and dissipation in the magnitude of adownstream transmitted pressure wave. The transient pressure wave isable to expand into more space and the pressure decreases. In so doing,the expansion causes the wave pressure energy to simply convert backinto internal energy without doing work. So, conduit diameter increasesand conduit tees with combined downstream conduit areas equal to orgreater than that of the incoming conduit always cause a dissipation inthe work potential of the transient pressure wave impulse.

Finally, the phenomenon explains why the presence of air in the conduitor system can significantly reduce the work potential and work output ofa pressure transient work process and system. Because air is quitecompressible while liquids are not, the liquid can easily expand andcompress any air within the system doing little work in the processwhile allowing much of the liquid pressure energy to convert back intointernal energy without doing work.

Confined Liquid Transient Energy Work Processes

As discussed above regarding dissipation of transient pressure energy,it can be concluded that the transient pressure energy, P/ρ, of acompressed liquid will convert back to internal energy, u, (seeEquations (11) and (12)) when the compression is relieved unless thecompressed liquid is made to do work as it expands to its equilibriumvolume. Further, it can be concluded that the amount of work that isdone depends entirely upon how easily the expansion is accomplished. Forexample, as discussed, expansion of the liquid into a confined air spacedoes work as it compresses the air, but the air pressure raises littleas compared to the large transient pressure drop experienced by theliquid as it expands to its equilibrium volume. In that case, most ofthe transient liquid pressure converts back to unavailable internalthermal energy in the liquid and so does little useful work incompressing the air as compared to the transient pressure energyavailable for doing work. The following provides discussion and analysisof several transient pressure energy work processes, when applicable,and how such processes can be made to efficiently do continuing usefulwork.

1. Water Hammer Work Processes

Described hereinabove is an explanation for how the transient pressurewave returning to the liquid source in a water hammer process can havemore total energy than the potential energy of the liquid source. Theadditional energy comes from conversion of part of the internal energyof the liquid (u) into pressure energy (P/ρ). That is why, for thatinstant just before flow reverses and water flows back into thereservoir, the pipeline pressure is greater and at higher potentialenergy than it originally started with.

The water hammer process discussed hereinabove describes a rapidlyclosing valve in a pipeline that creates a series of alternating highand low transient pressures and forward and reverse flows in thepipeline commonly known as water hammer. The work performed by waterhammer is in causing the alternating liquid flow and alternatingflexures of the pipeline and valve walls. The transient pressure energyis thus dissipated by the flexures of the pipeline and friction with thealternating flowing liquid. If the pipeline or valve walls are notsufficiently strong or flexible the transient pressures will cause thewalls to break. Many such hard lessons have been learned over the yearsby those who have designed, constructed, and operated pipeline systemsthat could not withstand water hammer pressures when they were createdby rapid changes in flow. Thus, though not directly useful, work isnevertheless done on the pipeline and valve walls and on the liquid asthe water hammer transient pressures dissipate.

Further, as discussed hereinabove, it is well known that the initialtransient pressure rise resulting from a rapidly closed valve isdirectly related to the speed of a pressure wave c_(p) (the speed ofsound) in the liquid filled pipeline. In turn that speed is directlyrelated to the rigidity or flexibility of the pipeline. The more rigidthe pipeline, the greater the pressure wave speed c_(p) and the greaterthe transient pressure rise, and conversely, the more flexible thepipeline, the lesser the wave speed and the lesser the transientpressure rise. Some important things can be learned from this well-knownbehavior.

The behavior can again be explained by analyzing the molecular forcesthat cause the pressure rise. In stopping a pipeline flow, a moreflexible pipeline material such as PVC expands and provides more spaceor volume for the liquid. So, the compressed liquid volume is closer toequilibrium and the internal molecular forces exert less pressure.Whereas, a rigid pipeline expands very little. So, the momentum andinertia of the liquid molecules packs the molecules closer together in asmaller space or volume and the internal thermal kinetic forces exertgreater pressure attempting to restore the equilibrium volume.

Two things can be learned from this phenomenon. The first is readilyapparent—that a rigid pipeline causes the conversion of more internalenergy into liquid pressure forces from the same liquid flow and so canoften provide greater opportunity and efficiency for harnessing theinternal energy of the flowing liquid. The second is more subtle, butjust as important because it has general application. It is that moreefficient designs will not dissipate the transient pressure energy byrelieving it without doing useful work. Flexing a pipeline is generallynot useful work and so reduces work efficiency by using and dissipatingpart of the available transient pressure energy that could otherwise bemade to do work.

Another subtle phenomenon that occurs to dissipate transient pressurewater hammer energy is what actually happens each time the wave frontreturns to the reservoir or water source. For that split second, as thewave front reaches pipeline inlet at the water source, the transientpressure at the inlet is much greater than the water source pressure.But at the moment the wave enters the water source, all wave pressure inexcess of the water source pressure is immediately dissipated byexpansion of the liquid into the water source. That expansion relievesthe excess pressure and does almost no work. Though it does push a smallamount of the water source liquid aside, no useful work is done and mostof the excess pressure energy converts back to unavailable internalthermal energy. The only pressure that then remains at the pipelineentrance is the water source pressure itself which then causes areversal of the pipeline flow and a pressure wave front travels backdown the pipeline. But, that pressure wave is at the water sourcepressure and not at the much higher pressure of the wave that had justreached and entered the water source. That pressure energy is dissipatedin the water hammer process back into internal molecular energy and isno longer available to do useful work.

As each succeeding pressure wave returns to the water source orreservoir, the pressure wave is smaller in magnitude due to the workdone by friction and the expansion and contraction of the pipelinewalls. And, in turn, each returning pressure wave is dissipated throughconversion back into internal molecular energy as it enters thatreservoir so that eventually, as the transient pressures are damped outand ended by friction and the work done on the pipeline walls, the onlyuseful pressure energy that remains is the reservoir pressure.

The fact that the water hammer cycle repeats itself, though successivelydampened, can be quite useful and taken advantage of in doing usefulwork, such as in the ram pump work process. The optimum efficiency forthe operation of a given system will depend largely upon how muchfriction and dampening occurs in each successive cycle. Optimumefficiency should be expected when the time lost in generating anothertransient is offset by the increased pressure energy available from thenewly generated transient versus that available from the increasinglydampened transients of the previous transient cycle set.

A work process that can increase the usable energy or useful work thatcan be done from water hammer involves the placement of a rapidlyclosing valve at the reservoir inlet to the pipeline. The valve israpidly closed just before the first transient reaches the inlet. Iftimed correctly and done quickly enough, the transient pressure can bereflected from the closed valve causing a near doubling of pressuredirected back toward the downstream valve and the reflected wave can bemade to do useful work in a ram impulse type work process as it returns.Any remaining transient pressure waves transmitting back up the pipelineto the inlet valve can also be made to reflect back in the same mannerand can also be made to do useful work.

2. Ram Impulse Confined Liquid Work Processes

Ram impulse work processes are processes that use positive transientpressures to do useful work. For example, ram pumps use positivetransient pressures to pump liquid. Adaptations can harness positivetransient pressures to do most any type of work as well. The ram pumpprocess is analyzed here first followed by analysis of adaptations fordoing any type of useful work.

a. Ram Pump Work Processes

As demonstrated hereinabove, the efficiency of the pumping portion ofthe operating cycle for a functioning ram pump is always greater than100 percent. That is because during the pumping part of the ram pumpcycle, part of the internal kinetic energy of the water has beenconverted to pressure energy and that pressure pumps the water to a muchhigher level than the elevation of the water source. Thus, theefficiency of the pumping part the ram pump cycle is much greater than100 percent as determined by Equation (8).

The assumption to date is that the overall process must have anefficiency of less than 100 percent and so the conversion of internalenergy into pressure energy is just an interesting phenomenon with onlya limited application for doing work. But, it is a major assumption thathas unfortunately foreclosed further inquiry. The unfortunate assumptionis actually false. But, due to the inefficiencies inherent in the rampump work process and an unfortunate focus on the overall powerefficiency of a ram pump system, that fact is not at first apparent andso has been missed until now.

First, it can be shown that overall system power efficiencies of greaterthan 100 percent can be achieved by ram pump systems. If instead offocusing on the overall power efficiency evaluated using Equation (6),one instead evaluates the resulting net energy efficiency of the systemone gets an entirely different efficiency result. The energy lost is theloss in the potential energy of the waste flow while the energy gainedis the gain in potential energy of the pumped flow. The net energyefficiency is then computed by dividing the gain in potential energy bythe loss in potential energy as follows:

$\begin{matrix}{E_{s} = \frac{P_{v} \times H_{p} \times \gamma}{W_{v} \times H_{s} \times \gamma}} & (13)\end{matrix}$

where:

-   -   E_(s)=Net total system energy efficiency    -   P_(v)=Pumped volume (ft³)    -   H_(p)=Resulting head of pumped flow (ft)    -   W_(V)=Wasted volume (ft³)    -   H_(s)=Wasted head or source head (ft)    -   γ=unit weight of water (lb/ft³)

The units for this equation are that of energy (ft-lbs/ft-lbs) which isdimensionally correct for computing the net energy efficiency of theoverall system pumping operation (the combined net energy efficiency ofthe operation of the upstream drive pipeline, the ram pump unit, and thedownstream discharge pipeline to its outlet). Because γ appears both inthe numerator and the denominator, it can be cancelled from the equationso that a simplified net system energy efficiency equation can beexpressed as:

$\begin{matrix}{E_{s} = \frac{P_{v} \times H_{p}}{W_{v} \times H_{s}}} & (14)\end{matrix}$

Now, let's use Equation (14) to evaluate the net energy efficiency,E_(s), of reported higher efficiency ram pump operations. Ram pump powerefficiencies, E_(p), of up to 80 and 85 percent, computed using thetraditional efficiency equation (Equation (6)) reportedly have beenachieved with commercially designed ramp pumps when pump head lifts,H_(p), are 4 to 3 times the head of the source fall H_(s) (“Using aHydraulic Ram to Pump Livestock Water”, Livestock Water Factsheet,British Columbia Ministry of Agriculture and Lands, January 2006). Usingthose reported efficiencies, a drive flow of 0.1 cfs with 10 feet ofdrive head and 40 feet and 30 feet of pumped lift respectively, pumpedflow should be 0.02 cfs and 0.02833 cfs respectively for 80 and 85percent traditionally computed power efficiencies (E_(p) in Equation(6)). That means in a time of one (1.0) second, pumped volumes should be0.02 ft³ and 0.02833 ft³ respectively. Waste flows should be 0.08 ft³and 0.07167 ft³ respectively. Substituting these values into Equation 14yields:

$E_{s} = {\frac{P_{v} \times H_{p}}{W_{v} \times H_{s}} = {\frac{0.02 \times 40}{0.08 \times 10} = 1.00}}$$E_{s} = {\frac{P_{v} \times H_{p}}{W_{v} \times H_{s}} = {\frac{0.02833 \times 30}{0.71678 \times 10} = 1.18}}$

Both of these energy efficiencies are 100 percent or greater showingthat under the right conditions and design, traditional ram pump systemscan have net energy efficiencies, E_(s), of up to 118 percent andgreater. The inventor's tests have verified ram pump efficienciesgreater than 150 percent while at least one published article reportstest results having nearly 200 percent energy efficiency when analyzedusing Equation (14). See “Hydraulic Ram Pump”, Teferi Taye, SeniorMechanical Engineer, Energy Division, Equitorial Business Group, AddisAbaba, Ethiopia, published in the Journal of the ESME, Vol II, No. 1,July 1998.

The problem with Equation (6) in the traditional power efficiencyequation for ram pump systems is in including the pumped flow, Q_(p), inthe denominator. That is correct if one desires to evaluate theefficiency of the power imparted to the pumped flow versus the totalpower required to operate the system including the power required toovercome upstream and downstream pipeline friction losses. However,Equation (6) ignores the fact that the power imparted to pumped flow,Q_(p), is converted to potential energy and can be reused. But, that isexactly what happens. Gravity is a conservative force and the pumpedflow is pumped against this conservative force so that its potentialenergy is increased. This gravity driven potential energy can be, andnormally is, reused in conveying the pumped water away from the ram pumpdischarge pipeline outlet. When the pumped flow, Q_(p), is taken out ofthe denominator of Equation (6), then the pumped power is divided by thewasted power and the result is the same as that computed from Equation(14) because the equation then computes the net efficiency of the systempower gain or loss rather than the total system power efficiency.Equation (6) is incorrect in analyzing energy efficiency because itignores or misses the fact that the power in the pumped flow is notlost.

So, now that it has been shown the ram pump system energy efficienciescan be greater than 100 percent, it is time to examine what causesdissipation of the transient pressures in the ram pump process. Thetypical ram pump process design has an overall traditionally computedpower efficiency ranging from 40 to 85 percent with 60 percentefficiency being common. In analyzing the inefficiencies of that pumpingprocess, first and foremost, expansion of the compressed liquid isaccomplished against the open atmosphere at the pumped water pipelineoutlet. As discussed above, that design is inefficient because it allowsthe expansion of the liquid against free air at the outlet without doingany further useful work. Whatever pressure energy there may have been inexcess of that needed to push water out of the outlet is dissipatedwithout doing work.

The air chamber does help in somewhat reducing that dissipation ofpressure energy, but only to a limited extent. Immediately before thepumping portion of the cycle, the air chamber pressure is at or verynear the outlet pressure. When the waste valve closes the transientpressure predicted by Equation (1) occurs at the valve and the pressurewave begins to travel back up the drive pipeline as the inertia of theliquid molecules packs the molecules closer together. The excesspipeline pressure forces liquid through the check valve into the airchamber compressing the air in the chamber to a pressure somewhat abovethe outlet pressure and forcing the uncompressed water column in theoutlet pipeline to move toward the outlet and discharge liquid out ofthe outlet. As the transient pressures in the pump and drive pipelinedrop to that in the air chamber, the flow tries to reverse and the checkvalve closes. The excess pressure in the air chamber then forces moreliquid out of the outlet until its pressure equalizes with that causedby the outlet elevation. So, the excess pressure created in the airchamber by the work of the transient pressure upon the air chambercaptures and preserves a portion of the transient pressure energy (partof the internal energy), which in turn, does some additional workpushing more water out of the outlet and overall efficiency is slightlyimproved. But, as pointed out above, because air is easily compressible,most of the excess pressure is dissipated without doing work as itexpands against the easily compressible air and process efficiencysuffers accordingly.

Analysis of the waste flow portion of the cycle also revealsinefficiencies. First, as the pumping part of the cycle ends, and thecheck valve closes, the remaining transient pressures in the drive pipeare at the outlet pressure. That causes a back pressure and flow back upthe drive pipeline to the source sufficient to relieve the pressure atthe waste valve and it reopens. So, part of the transient pressureenergy is used to do the useful work of reopening the waste valve. But,that work does not directly contribute to the efficiency of the overallwork output of the process.

If as in some designs, the check valve is spring operated, the springwill cause the valve to close before all of the transient pressure inexcess of the outlet pressure has been used in the pumping process. Inthat case, pump efficiency decreases. But, a spring operated valve issometimes necessary if the pump lift is not sufficiently high ascompared to the water source. In that case, there is not enough energyleft to cause the back flow needed to reopen the waste valve. So, thespring operated check valve preserves some of the pumping energy for theneeded reopening of the waste valve in the back surge process.

But, probably the most important inefficiency is in the waste flowportion of the cycle. First, the terms “waste flow” and “waste valve” donot properly describe their function. Rather “recovery flow” and“recovery valve” are better because the flow through the valve isnecessary to restore and recover the drive pipeline velocity back tothat needed for the next pumping portion of the cycle. Viewed in thatmanner, it becomes apparent what needs to be done to increaseefficiency. The recovery to maximum or optimum flow velocity needs tohappen as quickly as possible.

Testing shows that there is an optimum recovery flow velocity for rampump operation that produces the greatest pumping flow in comparison tothe amount of waste/recovery flow energy lost. Any lesser waste/recoveryvelocities result in lesser transient pressure energy and so less pumpedflow. While for any greater waste/recovery velocities, though resultingin greater transient pressures, most of the additional transientpressures are lost or dissipated in the air chamber or through thepumped water outlet. So, wasted energy increases in the waste/recoveryflow discharge while little to no additional pumping is accomplished.Thus, the pumping energy efficiency is the greatest when thewaste/recovery valve closes at the optimum waste/recovery velocity forthe head against which water is being pumped.

Further, another waste/recovery flow phenomenon affects the energyefficiency of ram pump operation. As was discussed hereinabove, when avalve is rapidly opened, there is an initial rapid increase in velocity.The incremental increase occurring in the flow is at first comparativelylarge—basically double the initial flow as the first transient lowpressure reaches the reservoir. But, as each successive transient lowpressure wave caused by the open valve reaches the reservoir, themagnitude of that incremental increase decreases rapidly and nearasymptotically as the flow velocity nears steady state conditions.

So, at first the rapid increase in flow velocity causes a rapid increasein available pumping energy. But as the waste/recovery valve remainsopen, the incremental increase in velocity and associated increase inavailable pumping energy rapidly decreases so there becomes increasingwaste/recovery flow for lesser and lesser increases in velocity and thuslesser and lesser transient pumping energy. So, quickly the increasingwasted energy begins to cause increasing loss in pumping efficiency. Atthe point where the energy loss just begins to exceed the energy gain,the maximum efficiency has been reached and any further waste/recoveryflow decreases efficiency. In sum, the pumping efficiency suffers if thewaste/recovery valve closes too early or too late.

In many cases, these various losses of efficiency do not matter becausethere is sufficient waste flow energy in excess of the pumping energyneeded to allow ram pumps to be useful in a wide variety ofapplications. The inefficiencies are analyzed here to help understandthe energy losses in the overall ram pumping process so that moreefficient systems that can do work other than pumping of liquids can bedesigned.

If electricity is available, electrical opening and closing of the wastevalve can greatly improve pumping efficiency by constraining the wasteflow to a range of optimum efficiency. The efficiency that can beachieved in any situation depends mostly upon the drive pressure fromthe source and the drive pipeline length and rigidity.

In similar manner to the water hammer process, the drive pipeline lengthand rigidity directly determines the cycle time for hydraulicallyoperated ram pump systems. It does so in three ways. The drive pipelinelength affects: 1) the time length of a transient pressure impulse(whether high or low pressure), 2) the magnitude of the drive pipelinefriction loss, and 3) the time length of energy loss through the wastevalve. The drive pipeline length affects the energy loss both in termsof the magnitude of the friction loss and the time required to reach anygiven flow velocity in the drive pipeline and through the waste valve.The longer the length or the less rigid the pipeline, the longer timerequired for the velocity to increase. But, conversely, the longer thepipeline length and the lesser the pipeline rigidity, the longer thetime of the transient pressure impulse available to do work. That timelength is based on the momentum or “freight train” principle. Thegreater the mass of the liquid being either stopped or started, thelonger the time that it takes to fully start or stop. And the longertime a force is applied, the greater the work that can be accomplishedand thus the higher the energy efficiency. So, the energy efficiency fora given pipeline length is determined by the overall balance between thesource drive pressure, the friction loss, the pipeline rigidity, thetime length of the transient pressure impulse, and the time length offlow and energy loss through the waste valve.

b. Ram Piston Work Process

An improvement on the ram pumping work process is to replace the checkvalve, air chamber, and outlet pipeline with a piston in a cylinderconnected to the drive pipeline as shown in FIGS. 2A-2C. The oppositeend of the cylinder is open to the atmosphere. The piston is sealedagainst the cylinder walls so that no liquid can escape to the open sideof the cylinder and drives a piston rod connected to any useful devicethat can be driven by the reciprocating motion of the piston.

This design can reduce or eliminate the inefficiency of dissipatingexcess pressure energy to the atmosphere at the pump discharge lineoutlet, but requires that the load on the piston must be sufficient toavoid dissipating the energy as well. The size of the piston matters aswell and needs to be balanced against the source pressure and volume andlength of the liquid in the drive pipeline. Otherwise, source pressureand pipeline length affect the energy efficiency of the work process inthe same manner as in the ram pump system.

The operation is much like that of a ram pump, but with some importantdifferences. Like the ram pump operation, a flow recovery/waste valveopens and begins to discharge liquid. As the liquid accelerates andvelocity begins to stabilize, the flow/recovery waste valve shutsstopping the flow. The resulting pressure transient pushes the pistonoutward in the cylinder doing work upon whatever is connected to it. Asthe transient pressures drop, the load on the piston is sufficientlymaintained such that it has sufficient power and force to push theliquid back out of the cylinder at normal pressure and the pistonreturns to its original position in close proximity to the drivepipeline. The pushing of the liquid out of the cylinder creates areverse flow back up the pipeline to the source. As the piston reachesits original position and stops, the reverse flow continues for a momentunder its own momentum. That moment of reverse flow causes the pressureto drop at the flow recovery/waste valve causing it to reopen and thecycle begins again.

Again as with a ram pump, replacing the hydraulically operating valvewith an electronically controlled flow recovery/waste valve can enhanceoperating efficiency by maintaining recovery flow at its optimalminimum. In that case, the stroke of the piston and the piston size isbalanced against the cylinder volume, the drive pipeline length andvolume, and the drive pipeline normal pressure to achieve the greatestoverall piston work efficiency. The back flow becomes unnecessary toopen the recovery flow valve, and so can be minimized or eliminated.But, if the cylinder liquid is exhausted through the recovery flow valveby the opening of the recovery valve on the down stroke, whatever flowis discharged from the cylinder prevents or reduces velocity in thedrive pipeline for the next cycle and so reduces efficiency unless keptto a minimum.

With the exception of the return discharge of liquid from the cylinderback to the pipeline, the ram piston system alleviates most of theinefficiency of a ram pump system. In so doing, overall systemefficiencies much greater than 100 percent are possible because again,it is not the energy of the recovery/waste flow that causes thetransient pressures, but the inertia of the liquid molecules in thedrive pipeline.

c. Ram Turbine Work Process

A ram turbine work process functions basically the same as a ram pistonwork process with the piston and cylinder assembly replaced by a turbineassembly. Two basic types of ram turbines are the rocker-type turbineand the flow-through turbine. A diagram of the rocker-type turbine isshown in FIGS. 3A-3C. One or more of the blades are initially in closeproximity to the flowing liquid in the drive pipeline. As a transientpositive pressure is caused by any means in the pipeline, the turbineblades are driven in the sealed turbine housing away from the drivepipeline. As the positive transient pressures end, the rotation of theturbine is reversed and the turbine is rotated back by any means to itsoriginal position with its blade or blades again in close proximity tothe drive pipeline for the next positive transient pressure. Thus, themotion of the turbine is a rocker-type back and forth motion whichdrives by any means any device connected to it in a reciprocatingfashion much like the ram piston work process.

For the flow-through ram turbine, an outlet with a check valve is addedon the downstream side of the turbine as shown in FIG. 3A that outletsto any suitable location or pipeline and the turbine is operated torotate in a full circle. The turbine blades retract or fold over on theoutlet side so that upon the production of positive transient pressurein the drive pipeline, the transient pressurized liquid is dischargedthrough the turbine and out through the check valve causing the turbineto rotate and do useful work upon any device connected to it.

3. Downstream Momentum Confined Liquid Work Process

In a downstream momentum work process, upstream flow is quickly slowedor interrupted in a pipeline by any means. The momentum of thedownstream liquid causes the liquid to continue moving exerting a lowpressure, or suction pressure, on the upstream side of the liquid columnwhere the flow has been slowed or stopped. That low, or suctionpressure, continues to drop until either: (1) vapor pressure is reached,(2) the downstream liquid column is stopped by friction and upstream anddownstream pressure differences, or (3) the downstream liquid columnvacates the pipeline through a downstream exit.

If the drop of pressure at the initial point of velocity change issufficient to reach vapor pressure, the water column ruptures, thepressure stabilizes at vapor pressure, and a vapor cavity forms andgrows until the downstream liquid stops or exits from the pipeline.Thus, for this work process the minimum low pressure that can be exertedis that of vapor pressure.

So, this work process has some limitations and is less versatile.However, the process can still be quite useful. It can be used to exerta low, or suction pressure, to move a piston, turbine, or any usefuldevice, or to pull liquid into a pipeline, container, or reservoir. Itcan also be used to take pressure off of a device so that it can beeasily moved or opened similar to the re-opening work action of reverseflow on a ram pump waste valve.

Finally, if a vapor cavity is formed and flow is able to reverse due toupstream or downstream pressure conditions, the reverse liquid flow andpressure that travels back toward the vapor cavity causes the cavity tocollapse. At the moment of complete collapse, a positive pressuretransient equal to equations (1) or (2) is generated that will travelback up the pressure conduit and can be used to do work in a ram impulseor other such work process.

But, again if the flow does not reverse, the momentum force of theflowing liquid column remains available for doing work until it comes torest. If the water column does not rupture, the effect of momentum forcemust be evaluated using the compressible liquid impulse momentumequation: P_(i)=−ρ c_(p) v; the minus sign denoting a reduction inpressure. If the water column does rupture so that a vapor cavity formsin the pressure conduit and begins to grow, the motion and momentum ofthe remaining water column in the pressure conduit acts as rigid bodymotion and can be evaluated using incompressible liquid flow equations.

The total available energy for doing work using the separated watercolumn momentum is equal to the kinetic energy, ρv²/2 or v²/2 g, plusthe vapor pressure P_(v) force energy, minus friction and any otherenergy losses that might apply. The friction loss can be evaluated usingthe well-known Darcy-Weisbach equation or other acceptable liquid flowfriction loss equations. The general equations for evaluating work doneare:

Available Work Energy Head (ft)=(v ²/2g+P _(v)/γ−friction loss(ft)−Other losses (ft))

-   -   where γ=unit weight of water=62.4 lbs/ft³    -   or

Available Work Energy (ft-lbs)=m (v ²/2+P _(v)/ρ−friction loss(ft-lbs)−Other losses (ft-lbs))

-   -   where m=total mass of water remaining water column.

4. Work Processes for Increasing Confined Liquid Transient PressureEnergy

Several confined liquid work processes are available for enhancing andincreasing the transient pressure energy available for use inconjunction with other transient pressure work processes.

a. Passive Confined Liquid Work Processes for Increasing PressureEnergy.

Passive confined liquid work processes are processes that do not requireadditional outside actions once a transient pressure wave has beengenerated to convert internal energy to pressure energy or vice versa.Rather passive work processes take advantage of changes in the physicalconfiguration and properties of a conduit system to convert internalenergy into increased pressure energy.

For example, as discussed herein, a traveling transient pressure waveimpulse that encounters a dead-end or closed valve at the end of themain or lateral conduit can double the pressure of the reflected wave.Thus, reflection of transient pressure waves at a dead-end or closedvalve can dramatically increase the conversion of internal energy intohigher pressure having dramatically higher work energy potential for usein transient pressure work process and production devices.

Other passive confined liquid work processes that convert additionalinternal energy into pressure energy include a decrease in conduitdiameter or area, or an increase in conduit wave speed, or both.Internal energy is converted into a higher pressure wave impulse as thewave impulse transmits through and into a diameter or area decrease orinto a more downstream rigid conduit with a higher wave speeddownstream. Likewise, a conduit tee with downstream conduits of combinedarea less that the incoming wave impulse conduit or of greater wavespeed also convert the transmitted wave to a higher pressure impulse.Thus, simply decreasing the downstream conduit diameters or areas, orincreasing the downstream conduit wave speeds, converts more of theinternal energy of the downstream liquid into pressure energy that thencan be made to do work on work production devices.

However, the converse is true with reflected wave and returning waveimpulses as they return and pass back out of the downstream conduit intothe upstream conduit. This fact does not matter for work processes thatdo not depend upon repetitive wave impulses acting upon work producingdevice. But, even for work processes that do depend upon repetitive waveimpulses, the net effect can still be positive depending upon the natureand timing of the impulses returning into the upstream pipeline becausereturn impulses are additive to the pressure already present in theupstream conduit at the time of each impulse wave return to the upstreamconduit. With good design, the pressure in the upstream conduit can beincreased by wave impulse reflections back from the diameter or otherconduit change or from reflections at the upstream end of the upstreamconduit.

b. Valve Closing Confined Liquid Work Process

In this process, the closing or partial closing of valve either upstreamor downstream can be used to prevent pressure energy dissipation and toconvert additional internal energy into pressure energy. The fullclosing of the valve at the right time can create a reflection anddoubling of the wave impulse in the reverse direction while preventingtransmission of the wave impulse through the valve where it mightotherwise dissipate into a supply reservoir or other system conduit orcomponent.

Or, a diameter change at the right moment can cause an increase inpressure in the transmitted wave just upstream of a ram piston, ramturbine or other transient pressure work process device, or can cause apartial reflection of the wave impulse in the reverse directionincreasing pressure in the reverse direction.

c. Zero Initial Velocity Confined Liquid Compression Work Processes forIncreasing Pressure Energy.

At least two processes are available for converting liquid internalenergy into pressure energy for doing transient pressure wave impulsework that do not require the liquid to be initially in motion to causethat conversion. These processes include piston or mechanicalcompression and liquid injection compression.

(1) Piston or Mechanical Liquid Compression Work Process

In this process, a conduit or vessel having a piston or similarmechanical device at one end or at the end of a connected liquid filledlateral pressure conduit line is filled entirely with lower pressureliquid and closed at both ends so that the conduit or vessel and pistonconfines the liquid. Force is then applied to the piston or mechanicaldevice causing it to move toward the liquid filled and confined conduitspace and thus pressurize the liquid filling the vessel or conduit. Thepressurized liquid can then be released into a downstream liquid filledpressure conduit or vessel to cause a transient pressure wave impulse orset of transient pressure wave impulses in the entire liquid filledsystem. If the surface area of piston or other mechanical device issmall compared to the force applied to it, high pressures are created inthe liquid with little work or required energy in comparison to the workaccomplished when the pressurized liquid is released and made to drive atransient pressure work production process.

(2) Liquid Injection Liquid Compression Work Process

In this process, relatively low pressure liquid is introduced through avalve into a closed conduit or vessel until the conduit or vessel isfilled. The low pressure liquid valve is then closed so that the liquidis confined in the conduit or vessel. Pressurized liquid or liquid at ahigher pressure, is then forced by liquid pressure into the conduit orvessel through a second valve that is opened until all of the liquid inthe conduit or vessel to a pressurized to a desired pressure. Thepressurized liquid valve is then closed. The pressurized liquid in thevessel or conduit can then be released into a downstream liquid filledpressure conduit or vessel to cause a transient pressure wave impulse orset of transient pressure wave impulses in the entire liquid filledsystem. This transient pressure wave impulse or set of impulses can thenbe made to do work in a transient pressure work device process. The workand energy that can be produced in the transient pressure work process,can be significantly greater than the work and energy required to fillthe conduit or vessel with low pressure liquid and to pressurize thatliquid by introducing pressurized liquid into the conduit or vessel.

Referring again to FIG. 1, the liquid flow volume within a transientpressure producing cycle of the system 1 can be minimized for achievingminimum energy loss while doing the useful work desired. The workefficiency is a function of the amount of work/energy expended versusthe amount of work done on the device 16. The energy expended isdirectly related to the volume of liquid flow that passes through thetransient pressure drive 15 from the time the flow first starts (orfirst begins to increase) in the pressure drive component 15 from theliquid source 10 and through the drive conduit 11 to the time the flowis stopped (or slowed) by the transient pressure drive device 15 toproduce high transient pressures. The velocity of that flow increasesnear asymptotically toward the steady state velocity. At first the flowvelocity through the transient pressure drive device 15 increasesrapidly to near the steady state velocity with the remaining velocityincrease toward the steady state velocity occurring more gradually overa comparative much longer period of time. Meanwhile, energy is expendedto cause the liquid flow from the liquid source 10 through the driveconduit 11 and the transient pressure drive device 15. Since themagnitude of a transient pressure resulting from the stopping (orslowing) of a liquid by the transient pressure drive device 15 dependson the magnitude of the liquid flow velocity through the device 15, thegreatest transient pressure work process efficiency is achieved if theflow is stopped (or slowed) by the transient pressure drive device 15after the rapid increase in velocity while flow volume through thetransient pressure drive device 15 is low compared to the flow velocitythat is reached. Allowing the flow through the transient pressure drivedevice 15 to continue thereafter decreases work efficiency because theflowing liquid expends energy while achieving little comparative gain inthe amount of work that can be done by transient pressures and thetransient pressure drive device 15 when the liquid flow is stopped (orslowed).

In one aspect, the process of the system can entail the coordination ofthe hydraulics, design, and operations of the liquid source 10, thedrive conduit 11, and transient pressure drive device 15 components tominimize the liquid flow volume flowing in the pressure driveconduit/source conveyance component 11 and through the pressure drivedevice component 15 during a transient pressure producing cycle whileattaining a maximum flow velocity within an optimum range for producingthe liquid pressure transients within the two components (11 and 15)that optimum range being the velocity range wherein any lower maximumvelocity or any higher maximum velocity appreciably reduces thework/energy efficiency of the transient pressure drive device component15 in doing work on the device 16 from that work efficiency achieved bythe transient pressure drive device component 15 when maximum flowvelocity is within the optimum range. The process can thus result inoptimum useful work being done by the pressure drive device 15 at anoptimally minimized energy and liquid loss from the flow of the liquidthrough the pressure drive conduit 11 and the transient pressure drivedevice 15. The optimum work/energy and liquid efficiency range can befound for any system through testing, and can be estimated throughcomputations of the cycle work done versus the cycle flow volume andcycle energy used (energy lost) in reaching various pressure driveconduit maximum flow velocities. In one aspect, the process of FIG. 1can be more efficiently done using the zero initial velocity workprocess described hereinabove.

The process work/energy efficiency is computed by dividing the work doneby the transient pressure drive device 15 on the device 16 by theoverall energy lost from the release of liquid from the liquid sourcecomponent 10 through the pressure drive conduit 11 and through thetransient pressure drive device 15 into the outflow conduit 14. For areturn system, the energy used or lost (such as friction loss) inpassing the liquid through the outflow conveyance component 14, the heatsource 13, and returning the liquid through the liquid return conduit 12is also included in the energy used or lost. The process liquidefficiency is evaluated by dividing the volume of liquid that isreturned by the return conduit 12 to the liquid source component 10during any selected period of time by the volume of liquid that issupplied from the liquid source component 10 during the same period oftime.

As illustrated in FIGS. 2A-12, systems in accordance with the presentdisclosure can include various configurations of transient pressuredrive devices, drive components, and/or other system components. Forexample, as shown in FIGS. 2A-2C, a system can, in some aspects,resemble a typical “ram pump” in which liquid is gravity fed at avertical height difference 9 to the transient pressure drive device 15from the liquid source 10. The embodiment shown, however, includes atransient pressure drive device component 15 with a drive component 15 acomprising a “ram piston,” and a transient pressure producing outflowvalve unit 15 b, which can provide higher efficiency for a typical “rampiston.”

In operation, the outflow valve unit 15 b is opened causing liquid toflow from the liquid source component 10 through the pressure driveconduit component 11, the outflow valve 15 b, either dischargingdirectly to the surroundings through the outflow valve 15 b, ordischarging into the conduit 14. The liquid flow velocity increases inthe conduit 11 and the outflow valve 15 b until the force of the flowthrough the outflow valve 15 b causes the outflow valve 15 b to quicklyclose. The sudden closing of the outflow valve 15 b causes high liquidtransients that drive the ram piston of the drive unit 15 a outward,which in turn drives, and does work upon, the device 16 to the driveunit 15 a. The ram piston of the drive unit 15 a is returned to itsoriginal position (FIG. 2B) by gravity, mechanical, or other means.

The “ram piston” is shown in more detail in FIGS. 2B and 2C. Forexample, as shown, a piston 300 and piston rod 301 are mounted in acylinder 302 connected to the flow path 305 and the conduit 11. Thecylinder 302 can be constructed so as to have low, or atmospheric,pressure on the opposite side of the piston 300 from the conduit 11 andthe piston 300 can have seals 304 that contact the cylinder wall 302 andprevent leakage of liquid from the conduit 11 past the piston 300 to itslow pressure side. In FIG. 2B, the piston 300 is positioned at aninitial position prior to a transient pressure being produced in theconduit 11. The piston may be most efficient when it is in closeproximity and/or adjacent to the liquid flow path 305, as shown. Astransient pressure is produced by the closing of the outflow valve 15 band thereby stopping the liquid flow, the transient pressure pushes thepiston 300 and piston rod 301 outward and away from the conduit 11within the cylinder 302 toward its low pressure side, as shown in FIG.2C, driving and doing work upon the device 16 driven by it. As thetransient pressures end, the piston 300 is returned by gravity,mechanical, or other means to its original position (FIG. 2B) near theconduit 11 so that the piston 300 is ready to be again driven by thenext transient pressure produced.

The liquid that enters the cylinder 302 is pushed back out by thereturning piston 300 and back up the conduit 11 into the liquid source10. As the piston stops pushing the liquid backwards back up the conduit11 and back to the liquid source 10, the momentum of the backward liquidflow relieves the pressure against the outflow valve 15 b and itreopens, thus beginning the cycle again.

In one aspect, the piston 300 can be stopped by any means while theliquid that is entering the cylinder 302 from the conduit 11 as thepiston 300 moves away from the conduit 11 has sufficient remainingmomentum to cause a second pressure transient in the cycle. That secondpressure transient can travel back up the pressure drive conduit to theliquid source and cause a backward flow in the pressure conduit 11 tothe liquid source. The momentum of the backward flow can relieve thepressure against the outflow valve 15 b so that the outflow valve 15 bcan reopen and starts the cycle again. In another aspect, the “rampiston” drive unit 15 a can be operable with any transient pressureproducing valve or element 15 b, such as any quick operatingmechanically or electrically operated valve or other quick moving valvesor devices that produce repeating and cyclic transient pressures.

In addition, the work load of the device 16 directly or indirectlydriven by the piston 300 and piston rod 301 can be maximized and matchedwith the piston 300 travel distance within the cylinder (the pistonstroke or the distance the piston 300 travels between the pistonpositions in FIGS. 2B and 2C) to produce maximum work while requiringminimum piston 300 travel distance (the piston 300 movement distancebetween positions FIG. 2B and FIG. 2C) and expulsion of liquid back outof the cylinder 302 during the return stroke of the piston 300 as itreturns to its original position (FIG. 2B). Minimizing the amount ofliquid that needs to be expelled from the piston cylinder 302 back intothe conduit 11 and pressure drive conduit flow path 305 on the returnstroke by maximizing the device 16 work load can increase energy andliquid efficiencies. It can do so, for example, by reducing andminimizing the volume of flow required to reach the desired flowvelocity for producing the next set of pressure transients in the nextcycle.

Finally, it should be noted here that the larger the piston, the greaterthe work that can be done. However, a large cylinder can act as a suddenenlargement and reduce pressure waves coming into the cylinder. So, thepiston size needs to be balanced against the pressure wave reductionsthat occur. Further, the piston should be as close as possible to thewall of the conduit so the initial largest pressure waves act withlittle to no reduction. Thereafter, a large cylinder with a smallerentrance acts as a resonance chamber and can do more work if properlydesigned.

FIGS. 3A-3C illustrate other embodiments of a drive component, inaccordance with the present disclosure. In these embodiments, the drivecomponent can comprise a “ram turbine,” which can be utilized in thesystem illustrated in FIG. 1 or substituted for the ram piston of FIGS.2A-2C. In this embodiment, the ram turbine drive component can comprisean enclosed vane-type turbine 500 mounted in close proximity andadjacent to the conduit 11 flow path 507 and sealed against the sealedhousing 501 such that leakage of liquid past or through the turbine 500and turbine 502 is minimized or prevented. As transient pressures arerepeatedly and cyclically produced in the conduit 11 by stopping orsubstantially slowing the liquid flow, the transient pressure pushes oneor more of the turbine vanes 502 away from the pressure drive conduitflow path 507 thereby turning the turbine 500 and drive shaft 503 doingwork on any device/thing driven by the drive shaft 503 while expellingliquid under lower pressure through an optional outlet 505 and outletcheck valve 504 connected to the downstream or low pressure side of theturbine housing 501. The liquid is expelled through the optional checkvalve 504 and outlet 505 as the turbine turns and the vanes retract 508within or bend down against the turbine body 500 to fit within and sealagainst the sealed turbine housing 501. Each retracted or bent over vane508 remains retracted within or bent against the turbine body 500 untilit has rotated around to the conduit 11 side of the turbine where thevane 502 is caused any means to again extend out and away from theturbine body 500 to be ready to be driven by the next transientpressure.

As the transient pressures become sufficiently dissipated by doing workpushing the turbine vanes 502, the optional outlet check valve 504 canclose and the turbine 500 can stop. In one aspect, the outlet checkvalve 504 can be set or designed to close prior to full transientpressure dissipation through pushing the turbine. In another aspect,without the check valve 504, the transient pressure can continue to turnthe turbine body 500 and drive shaft 503 until the transient pressuresno longer have sufficient strength to turn the turbine 500 and driveshaft 503. At that time, whatever transient pressures are left can bequickly dissipated in the conduit 11.

When the next pressure transient set is produced in the conduit 11, thedrive vanes 502 are again driven away from the conduit 11 flow path 507turning the turbine 500 and drive shaft 503 while the optional outletcheck valve 504 again opens and allows liquid to expel from the turbine500 and its vanes 502. The turbine 500 inlet, outlet, and outlet checkvalve 504 can be constructed at any location around the circumference ofthe turbine so that the locations are not limited to that shown in FIG.3A, but can be constructed in any suitable location for the particularapplication.

The ram turbine can also be made to function as a substitution for theram piston of FIG. 2A in the following ways. In one aspect, if theoptional check valve 504 is used, the check valve can be set or designedto close at a high enough pressure to stop the flow through the turbineand cause transient pressure backflow back up the conduit 11 that willrelieve the pressure on the outflow valve 15 b and cause the outflowvalve to reopen and begin a new cycle. In another aspect, the turbine500 can be suddenly stopped by any means so that remaining transientpressures will cause backflow back up the conduit 11 to relieve thepressure on the outflow valve 15 b and cause the outflow valve to reopenand begin a new cycle.

FIGS. 3B and 3C illustrate an embodiment of a rocker-type ram turbine,which can be utilized in the system illustrated in FIG. 1 or substitutedfor the ram piston of FIGS. 2A-2C. In FIG. 3B, an enclosedvane/rocker-type turbine 500 can be mounted in close proximity andadjacent to the conduit 11 flow path 507 and sealed against the sealedhousing 501 such that leakage of liquid past or through the turbine 500and turbine 502 is minimized or prevented. As transient pressures areproduced by stopping or substantially slowing the conduit 11 liquidflow, the transient pressure pushes one or more of the drive vanes 502away from the drive conduit flow path 507, thereby turning the turbine500 and drive shaft 503 to the position shown in FIG. 3C and doing workon a device driven by the drive shaft 503 as it turns. As the transientpressures become dissipated by doing work pushing the turbine vanes 502and rotating the turbine 500 and turbine drive shaft 503, the work loadon the turbine drive shaft 503 from the device being driven eventuallycauses the turbine 500 to stop at the position of FIG. 3C. The rotationdirection of the turbine 500, vane 502, and drive shaft 503 is thenreversed by any means (gravity, mechanical, electrical, or other means)in a rocker-type return motion that returns the turbine and vanes backto the original position near the conduit 11, without the drive shaft503 device work load, to be ready to be driven by the next transientpressure (the position of FIG. 3B). The reverse rotation of the turbineand vanes (from the position of FIG. 3C back to the position of FIG. 3B)expels the liquid that pushed the vanes 502 back into the conduit 11 andthe cycle is ready to begin again. Though liquid must be expelled by theturbine vanes 503 to the drive conduit flow path 507, the returnrotation from the position of FIG. 3C to the position of FIG. 3Brequires less work because no device work load is applied to, or drivenby, the drive shaft 503 during the return.

In this process, the work load of the device directly or indirectlydriven by the ram turbine drive shaft 503 can be maximized and matchedwith vane 502 travel distance to produce maximum work while requiringminimum expulsion of liquid back out of the turbine housing 501 into theconduit 11 during the return rotation of the ram turbine assembly (500,502, 503) as it returns to its original position (FIG. 3B). Minimizingthe amount of liquid that needs to be expelled back into the driveconduit 11 and drive conduit flow path 507 on the return rotation canincrease energy and liquid efficiencies because it can reduce andminimize the volume of flow required to reach the desired maximumconduit 11 flow velocity in the drive conduit flow path 507 forproducing the next set of pressure transients in the next cycle.

The rocker-type embodiment of the ram turbine can also be made tofunction as a substitute of the ram piston 15 a of FIG. 2A. Therocker-type ram turbine can hydraulically function in a similar way asdescribed for the ram piston 15 a and can operate in similarreciprocating back and forth action. That action alternately receivestransient pressurized liquid into the turbine housing 501 while doingwork and expels pressure dissipated liquid back to the conduit 11 inreciprocal motion to and from the positions of FIGS. 3B and 3C in likemanner to the ram piston 15 a reciprocal processes. In addition, thatreciprocal return motion pushing liquid back into the conduit from therocker-type ram turbine can also cause the backflow that opens theoutflow valve 15 b of FIG. 2A, as well.

Although FIGS. 2A-3C illustrate specific embodiments of transient waveproducing elements or devices, it should be recognized that any suitabletransient wave producing element or device in accordance with thepresent disclosure can be included or substituted for the transient waveproducing elements or devices illustrated in these figures.

FIG. 4 illustrates another embodiment of a transient pressure drivedevice in accordance with the present disclosure that can be operablewith the system of FIG. 1. As shown in FIG. 4, the transient pressuredrive device 15 can comprise a liquid conduit, such as the drive conduit11, fluidly coupled to the liquid source 10, and configured such thathigh pressure transient wave travels through the liquid conduit towardthe liquid source. The liquid or drive conduit 11 can be operable tofluidly couple the transient drive device 15, and components thereof,with the liquid source 10. As with some other embodiments, thisembodiment of the transient pressure drive device comprises a transientpressure producing element, such as a valve 22, to cause the highpressure transient wave. In this case, the valve 22 is disposed in theliquid conduit 21 proximate the liquid source.

To begin a cycle, the quick acting check or control valve at theupstream end of the drive conduit 11 is at first open to allow flow fromthe source 10 down the drive conduit to the pressure drive device 15where the flow is discharged from the drive conduit. When the desiredvelocity is achieved in the liquid flow, the transient pressure drivedevice stops the flow or otherwise causes a high pressure transient wavethat travels back up the drive pipe at the speed of sound toward thesource. Immediately before or at the time the high pressure wave reachesthe one-way check or control valve at the upstream end of the driveconduit, the valve is caused to close either automatically from the highpressure or by electrical or mechanical control. The high pressure waveis then reflected by the closed valve causing a doubling of the pressureas it is reflected and travels back down the drive conduit to thepressure drive device where it drives or moves a mechanical device.

The driving of the mechanical device relieves the pressure at the deviceand a low pressure wave is generated that travels back up the driveconduit at the speed of sound toward the source. Immediately before orat the time the low pressure wave reaches the one-way check or controlvalve at the upstream end, the check or control valve automaticallyopens by the low pressure or is electrically or mechanically opened sothat liquid from the source is caused by its somewhat higher pressure toflow through the valve and down the drive conduit.

This liquid flow and somewhat higher source pressure wave then travelsback down the drive conduit to the pressure drive device where becausethe pressure is insufficient to drive the device the flow is againstopped and a new but somewhat reduced high pressure transient wave isgenerated that drives the device and travels back up the drive conduitand the liquid hammer or water hammer cycle repeats itself with thecheck or control valve alternately closing to reflect the high pressuretransient waves back down the drive conduit to the drive device andopening to allow liquid into the drive conduit immediately before or atthe time the low pressure waves return to the check or control valve.

When the energy of the water hammer has been sufficiently dissipated bydoing work and by friction so that it can no longer drive the drivedevice, the check or control valve at the upstream end automaticallyopens or is opened electrically or mechanically and liquid then againfreely flows down the drive conduit to the drive device starting anothercycle where the liquid is discharged from the drive conduit until thedesired velocity is again achieved and the transient pressure drivestops the flow or otherwise causes another high transient pressure waveto travel back up the pipe.

FIG. 5 illustrates still another embodiment of a transient pressuredrive device in accordance with the present disclosure that can beoperable with the system of FIG. 1. As shown in FIG. 5, the liquidconduit 11 can comprise a transition surface 23 a, between across-sectional area 24 a and a cross-sectional area 24 b, operable toreflect at least a portion of a transient pressure wave in the liquidtraveling through the liquid conduit. In particular, the transitionsurface illustrated is configured to reflect the transient pressure wavein a direction of fluid flow from the liquid source or toward the drivecomponent.

In one aspect, the transition surface can be located in the upperone-third of the drive conduit 11. When high pressure transient liquidor water hammer waves created in the drive conduit travel backwards upthe drive conduit, the high pressure waves encounter or impinge upon thesudden reduction in drive conduit diameter or area. The sudden reductionin area causes an immediate pressure increase that then travels as twonew higher pressure waves in both directions. One higher pressure wavetravels back up the smaller diameter conduit to the source and while theother higher pressure wave travels back down the larger diameter driveconduit to the pressure drive device where increased work is done by thehigher pressure. The magnitude of the pressure increase at the suddenreduction is given by the following well known and tested equation:

Pressure change=2A ₂/(A ₁ +A ₂)*incoming pressure

Where

-   -   A₁=incoming (larger conduit) cross sectional area    -   A₂=outgoing (smaller conduit) cross sectional area

The subsequent reverse returning pressure wave from the source travelsdown the smaller diameter portion of the drive conduit to the beginningof the larger diameter conduit. The returning pressure wave encountersthe diameter change at the beginning of the larger diameter conduit as asudden enlargement that causes a drop in the pressure wave as it travelsdown the larger diameter drive conduit. However, the sudden pressuredrop causes additional liquid to flow from the upstream smaller diameterconduit so that the mass flow rate of the preceding pressure wave in thelarge conduit is nearly restored but moving in the other direction backdown the larger drive conduit. When that wave reaches the drive device,another high pressure transient wave is created that drives the deviceand sends a higher pressure transient back up the larger diameterportion of the drive conduit and the process repeats until damped out byfriction and other losses.

The net result is greater work is done by each higher transient pressurewave that is reflected from the sudden reduction back down the largerdiameter conduit to the drive device. The process repeats until thewater or liquid hammer elastic energy is dissipated by friction, doingwork, and other energy losses.

A sudden reduction in the upstream portion of the drive conduit has thedisadvantage of not causing as large of a pressure rise as is possibleif the high pressure waves were fully reflected from a closed valve.But, it has the advantage of automatically causing higher pressurereflection waves without any moving parts or valves needing to beoperated quickly, without needing energy for operation, and withoutneeding maintenance. Particularly sudden reductions can be moreadvantageous in larger diameter systems where larger diameter valveshave slower reaction times that require much longer drive pipes.

FIG. 6 illustrates another embodiment of a transient pressure drivedevice in accordance with the present disclosure that can be operablewith the system of FIG. 1. The transient pressure device of FIG. 6 issimilar in many respects to the transient pressure device of FIG. 5, inthat the transient pressure drive device can comprise a transitionsurface. In this case, the conduit 11 can include a transition surface23 b, between a cross-sectional area 24 b and a cross-sectional area 24c, is operable to increase the pressure and transmit and reflect atleast a portion of a transient pressure wave in the liquid travelingthrough the liquid conduit. In particular, the transition surfaceillustrated is configured to increase the pressure in the direction offlow and reflect the transient pressure wave in a direction opposite offluid flow from the liquid source or away from the drive component 15 a.

A sudden reduction in the downstream portion of the drive conduitfunctions in nearly the same way as a transition surface in the upstreamportion of the drive conduit, except it is the pressure wavestransmitted through the sudden reduction into the downstream smallerdiameter drive conduit that do more work at the drive device.

When high pressure transient liquid or water hammer waves created in thedrive conduit travel down the drive conduit, the high pressure wavesencounter or impinge upon the sudden reduction in drive conduit diameteror area. The sudden reduction in area causes an immediate pressureincrease in each high pressure wave that simultaneously travels in bothdirections. One higher pressure wave travels back up the larger diameterconduit to the source and while the other higher pressure wave travelson through the reduction and down the smaller diameter drive conduit tothe pressure drive device where increased work is done by the higherpressure The magnitude of the pressure increase at the sudden reductionis again given by the following well known and tested equation:

Pressure change=2A ₂/(A ₁ +A ₂)*incoming pressure

Where

-   -   A₁=incoming (larger conduit) cross sectional area    -   A₂=outgoing (smaller conduit) cross sectional area

Transient pressure waves reflecting back from the pressure drive devicedrop in magnitude as they travel backwards up the smaller diameterconduit into the larger diameter conduit. The reflected lower pressurewave returning back to the drive device from the sudden area increasereduces the pressure against the device and can reduce work. So, in oneaspect, the upstream drive pipe can be as short as practical to reducethe time between returning pressure waves. As each returning sourcepressure wave travels back down the larger diameter conduit andencounters the sudden reduction, it is transformed into a higherpressure wave that then impinges on and drives the drive device as thedrive pipe flow is stopped and another high pressure transient pressurewave is created.

As with a sudden reduction in the upstream portion of the drive conduit,a sudden reduction in the downstream portion of the drive conduit hasthe disadvantage of not causing as large of a pressure rise as ispossible if the high pressure waves were fully reflected from a closedvalve. But, it has the advantage of automatically causing higherpressure waves toward the drive device without any moving parts orvalves needing to be operated quickly, without needing energy foroperation, and without needing maintenance. Particularly suddenreductions can be more advantageous in larger diameter systems wherelarger diameter valves have slower reaction times that require muchlonger drive pipes.

FIG. 7 illustrates yet another embodiment of a transient pressure drivedevice in accordance with the present disclosure that can be operablewith the system of FIG. 1. The transient pressure device of FIG. 7 issimilar in many respects to the transient pressure devices of FIGS. 5and 6, in that the transient pressure drive device can comprise atransition surface. In this case, the conduit 11 can include twotransition surfaces. A transition surface 23 a can be between across-sectional area 24 a and a cross-sectional area 24 b, and atransition surface 23 b can be between a cross-sectional area 24 b and across-sectional area 24 c. The transition surface 23 a can reflect atransient pressure wave in a direction of fluid flow from the liquidsource or toward the drive component 15 a, and the transition surface 23b can reflect the transient pressure wave in a direction opposite offluid flow from the liquid source or away from the drive component 15 a.

Thus, in one aspect, a pressure resonance chamber can be created from acombination of the transition surfaces placed at both ends of a largercross-sectional portion of the drive conduit. The resonance chamber canbe short or long and functions in the same manner regardless of lengthother than longer resonance chambers have greater friction and otherenergy losses than shorter resonance chambers.

High transient pressure waves created in or caused to enter a resonancechamber rapidly and alternately collide or impinge upon each end of theresonance chamber as the transient pressure waves reflect back and forthin the chamber. Each time a pressure wave collides or impinges upon thedownstream chamber end, the pressure increases and liquid spurts at highpressure from the chamber as a high pressure wave into the downstreamsmaller diameter drive conduit. The high pressure wave travels down thesmaller drive conduit to the pressure drive device where it doesincreased work on the pressure drive device.

Meanwhile at the same time that the pressure wave strikes the downstreamchamber end, a reflection pressure wave is generated that travels backtoward the other end of the chamber and impinges on the oppositeupstream chamber end. That impingement on the upstream chamber endincreases the pressure and reflects the wave back down the chamber whilesome liquid is spurted into the upstream smaller conduit. This upstreamflow quickly reverses as low pressure is created at the downstream endof the chamber by the spurting of the liquid into the downstream smallerconduit and by the reverse reflection wave.

This process repeats in a water hammer type process until the elasticenergy of the pressure waves is dissipated through friction and otherlosses. The entire resonating process is repeated when another hightransient pressure wave is created in or caused to enter the resonancechamber.

The main advantage of the resonance chamber is that it repeatedlyamplifies the transient pressure and sends the amplified pressure wavesdown the smaller drive conduit to do work on the transient pressuredevice. It functions automatically without any moving parts and so needsno outside control or operation, needs no additional energy to function,and needs little or no maintenance.

In one embodiment, the resonance chamber or double transition surfacescan be disposed at a dead end, such as at one end of the drive conduitor on a tee or branch line connected to the drive conduit.

FIG. 8 illustrates still another embodiment of a transient pressuredrive device in accordance with the present disclosure that can beoperable with the system of FIG. 1. As shown in FIG. 8, the transientpressure drive device can comprise a fluid chamber 25 a, 25 b in theliquid conduit 11. The fluid chamber can contain a compressible fluid toabsorb and reflect at least a portion of a transient pressure wave inthe liquid traveling through the liquid conduit. Thus, in one aspect,the fluid chamber 25 a, 25 b can function as a transient wave producingelement. In another aspect, the fluid chamber 25 a, 25 b can function asa drive component. In one embodiment, the fluid chamber 25 a can bedisposed in the liquid conduit proximate to the liquid source. Inanother embodiment, the fluid chamber 25 b can be disposed in the liquidconduit proximate to the drive component. In yet another embodiment, thefluid chamber 25 b can be disposed before or integrated into the drivecomponent 15 a.

Air chambers have been used in ram pump devices to even the out the flowin a ram pump outflow line. The air compresses slightly during eachpumping part of the ram pump cycle and then decompresses during thewaste flow part of the ram pump cycle. The result is a more steady flowup the outflow line.

But, air is highly compressible and actually dissipates much of thepressure energy available in higher pressure transients. For that reasonair filled chambers are also commonly used as devices that control andreduce of water hammer through dissipation of the high transientpressure energy. Nevertheless, the spring-type effect of the compressedair in a ram pump system actually stores a small amount of the higherpressure energy and improves ram pump performance.

However, for other applications, it can be desirable to replace the airin the air chamber with a compressible liquid that is much lesscompressible than air, but more compressible than the drive liquid (inmany cases water). The more compressible liquid momentarily stores theenergy of the higher pressure waves before being reflected back in thedrive conduit while being able to reflect much more of the lesserpressure waves toward the pressure drive device. Greater work efficiencycan thus result as more of the lesser pressure waves are caused to dowork along with the higher pressure wave energy. More of the higherpressure wave energy is at first stored as it compresses the liquid inthe liquid chamber and then is released to drive the pressure drivedevice as the pressure waves lessen and the more compressible liquidthen decompresses.

FIG. 9 illustrates another embodiment of a transient pressure drivedevice in accordance with the present disclosure that can be operablewith the system of FIG. 1. As shown in FIG. 9, the transient pressuredrive device can be configured to progressively reduce a load on thedrive component 15 a. In one aspect, this can cause more work to be doneby each set of high transient or water hammer type pressures created ina drive pipe by advantageously controlling the load that the pressuredrive device is required to drive or push. As a set of high transientpressures is created in the drive pipe, the first transient pressuresare the greatest with each succeeding transient high pressure becomingless and less as friction and other energy losses dissipate thetransient pressure energy. When transient pressures are required todrive against a constant load, all of the lesser pressure transientsthat do not have the strength to drive the load are dissipated and lost.If however, the load against the drive device is controlled so that theload needing to be driven becomes lighter and lighter as the transientpressures drop in energy, more overall work can be done because work isextracted from the lower transient pressures as well as the highertransient pressures.

A simple example involves a modification of a typical ram pump system,represented schematically in FIG. 9 by 15 c, where two valves areinstalled on tees at two elevations on a ram pump outflow pipeline. Whenthe waste valve of the ram pump closes, the high transient pressuresfirst pump water to the highest elevation at the end of the outflowline. Then just as the pumping would otherwise stop, the valve on thehighest tee is opened and the lesser transient pressures are able topump water to the elevation of that highest tee. Finally, just as thepumping would again otherwise stop, the valve for the lower tee isopened. The lesser transient pressures are able to pump water to theelevation of the lower tee. The net result is that some is water pumpedto the upper outlet of the outflow line, some water is pumped to thehighest tee elevation and some water is pumped to the lowest teeelevation. Whereas, without the reduction of pressure load provided byoutletting the water through each successively lower tee, the only waterthat would have been pumped would have been that water pumped to theupper outlet of the outflow line. Check valves in the outlet pipelinejust upstream of the tees can keep the pipeline filled with water. Thus,over time as the process is repeated over and over again more pumpingwork will be done. In one aspect, a mechanical device can continuouslycontrol the load on the pressure drive device to match the availablepressure transient magnitude and energy in order to extract work fromeach successively lower transient pressure and do more work from eachpressure transient cycle.

FIG. 10 illustrates still another embodiment of a transient pressuredrive device in accordance with the present disclosure that can beoperable with the system of FIG. 1. As shown in FIG. 10, the transientpressure drive device can comprise a pump 18 to deliver liquid to thetransient pressure drive device from the liquid source 10 via a conduit33. In one aspect, a pump 34 can be utilized to pump the liquid throughthe conduit 33. In another aspect, the pump can be operably coupled to apressure chamber 27 to deliver liquid to the transient pressure drivedevice. The pressure chamber can include a valve 28 a at an inlet end toreceive liquid from the liquid source 10 via a conduit 11 a, and a valve28 b at an outlet end to discharge liquid to the drive component 15 a.

This aspect of the system is analogous in some respects to an automatichydraulic jack because it uses the same simple principle of operation;that is, the process applies repetitive liquid pressure against a pistonwith valves that check and stop any backward liquid flow so that theapplied pressure and liquid flow is always directed forward against thejack piston and work load.

Tests have been performed on a 53-foot section of upstream ½″pressurized drive pipe, releasing water into a 26-foot section ofdownstream ½″ drive pipe and driving a 3″ piston at the far end of thedownstream drive pipe. Depending upon the load placed against thepiston, the work done against the piston was measured to be between 12and 27 times the amount of energy expended to pressurize the 53-footsection of upstream drive pipe (1200 to 2700 percent efficiencies). Asexpected the lighter loads had higher efficiencies than did the heavierloads because more of the dropping transient pressure waves were able todo work under the lighter loads. But, the upstream check valve usedtended to bounce and leak when slammed shut by the higher pressuresduring the tests. It is believed much better results can be obtainedwith a more stable and faster acting, non-leaking upstream check orcontrol valve.

In this process, the drive conduit is not pressurized by causing theliquid to flow in the drive pipe and then stopping that flow. Butrather, a part of the drive conduit is pressurized from a pressurizedliquid source or from pressure applied by a piston connected to theconduit.

In one embodiment, a check or control valve can be connected to theliquid source and to a tee at the upstream end of the drive conduit anda second valve, a control valve, is installed somewhere in thedownstream half of the drive conduit toward the pressure drive device.Installing the second valve at either the one-half or two-thirds pointson the drive conduit works. A third valve, the pressurization valve isinstalled on the tee and connected to a small pressurized liquid conduitcoming from the liquid source and including a pump or otherpressurization device that pressurizes a small amount of liquid in thesmall conduit to a desired pressure to be available for use during eachtransient pressure drive cycle. The entire drive conduit, which isconnected to the pressure drive device, is completely filled with liquidin a manner so that all air is removed. The following pressurized driveconduit work process can then begin:

-   -   1. The two valves installed in the upper part of the drive        conduit are closed.    -   2. Liquid is drawn from the liquid source and pressurized using        a pump, a piston, or any other means.    -   3. The pressurization valve on the tee at the upper end of the        drive conduit is opened causing a small amount of pressurized        liquid to flow into and pressurize the liquid in the portion of        the drive conduit between the two closed drive conduit valves to        the desired pressure.    -   4. The pressurization valve on the tee is then closed.    -   5. The pressurized liquid between the two valves is then quickly        released into the downstream portion of the drive pipe by        quickly opening the downstream control valve in the drive        conduit.    -   6. The opening of the downstream control valve causes repeated        high transient liquid hammer or water hammer type pressure waves        in the entire drive conduit. High transient pressure waves        travel down the drive pipe, slam into the pressure drive device,        and do work.    -   7. Each time a high pressure wave is reflected and travels back        up the drive pipe to the valve at the liquid source the valve is        closed just before the wave reaches the valve so that the high        pressure wave is reflected back down the drive pipe to the drive        device with doubled pressure minus the friction and other losses        incurred as the pressure waves travel up and down the drive        conduit.    -   8. As the high pressure transients drive and push the pressure        drive device, low pressure waves are caused that travel back up        the drive conduit to the liquid source.    -   9. Each time a low pressure wave reaches the check or control        valve at the liquid source, it opens and lets water into the        drive conduit from the liquid source.    -   10. In this way, the transient pressure energy is directed        forward in a ratcheting type repetitive water hammer action that        drives the pressure drive device doing work on the work device        component 16 of the process until the transient pressure energy        is expended.    -   11. The spent liquid in the drive device is then expended out of        the drive device, passed through the heat source 13 to restore        the internal molecular kinetic energy of the liquid and returned        to the source to complete the cycle.    -   12. The process of steps 1 through 11 are then repeated.    -   13. The work device 16 driven in steps 1 through 11 includes a        means for generating electrical power for operating the valves        and a control system for operating the valves in properly        synchronized manner as described here. That control system can        be mechanical or electronic.

In one aspect of the embodiment shown in FIG. 10, the check or controlvalve at the upstream end of the drive conduit 28 a and the fluid link11 a from the valve 28 a to the source 10 can be substituted, as shownin FIG. 11, by a combination enclosed and pressurized air cylinder 28 cand piston and rod assembly 28 d. In this embodiment, the piston isinstalled in the air cylinder such that the piston separates thepressurized air in the cylinder from the liquid in the pressure chamber27, which can function as a drive pipe in this aspect of the embodiment.The piston rod extends from the piston through the center of the aircylinder through the sleeved and sealed cylinder end that maintains theair pressure in the cylinder. At the other end of the rod outside of theair cylinder, the piston and rod assembly 28 d can be connected to anyelectro-mechanical device 28 e that can pull the rod and piston backagainst the air pressure in the cylinder causing liquid to enter thecylinder from the source, and then allow the piston to move forwardagainst the liquid while stopping any backward motion once the pistonbegins to move forward until the piston has reached the end of itsstroke. At that point, the piston is ready to be pulled back again andthe electro-mechanical device resets and pulls the piston back againstthe air in the cylinder causing liquid to enter the cylinder for anothercycle.

In this manner, the piston and rod assembly 28 d can be pulled backagainst the compressed air in the cylinder 28 c and then allowed to bepushed forward by the compressed air in a very rapid ratcheting motionthat moves the piston forward when each low pressure transient waveenters the cylinder and stops the piston when each high pressuretransient enters the cylinder. In this way, high pressure transientwaves can be doubled and reflected back down the drive pipe 27, whilethe low pressure waves and air pressure in the cylinder rapidly move thepiston in tandem with the flow of the liquid in the drive pipe toward todrive device at the downstream end of the drive pipe 15 a.

In general, the larger the area of the mechanical device driven by thetransient pressures, the greater the work done. However, a point isreached where any greater area causes sufficient pressure wave reductionfrom the sudden expansion of the pressure waves into the larger area atthe mechanical device to begin to reduce the work done.

The work process can require initial outside energy to start the processto operate valves and pressurize the drive conduit between the twovalves, and open the downstream control valve in the drive conduit tobegin the first transient pressure water hammer type cycle. Thereafter,the molecular elastic kinetic energy of the liquid harnessed and causedto do work is sufficient to continue the process in repetitive cycles solong as the molecular kinetic energy of the liquid is adequatelyreplenished and restored as it passes through the heat source, asdiscussed further hereinafter.

FIG. 12 illustrates yet another embodiment of a transient pressure drivedevice in accordance with the present disclosure that can be operablewith the system of FIG. 1. As shown in FIG. 12, the transient pressuredrive device can comprise a pump 18 to deliver liquid to the transientpressure drive device through the drive conduit 11. In one aspect, thetransient pressure drive device can comprise a valve 29 operable torelease liquid in the drive conduit pressurized by the pump toward thedrive component 15 a. The valve 29 can comprise a one-way control orcheck valve provided at the upstream end of the drive conduit. In oneaspect, a fast acting check or control valve can cause more work to bedone.

In one aspect, the pump provides the initial velocity and liquidmomentum in the drive conduit. In another aspect, the energy input tothe pump and valve operations can be provided by the heat energy inputfrom the heat source of the recycling process. The heat source canreplenish the process energy through heat energy transfer back into theliquid. In that way continuous work can be done without the need for abooster pump periodically powered by an outside energy source.

In some embodiments, the transient pressure drive device 15, such as thedrive component 15 a or a transient pressure producing element, canoperate in fully confined pressure conditions so that no part of thetransient pressure is dissipated through a nozzle or other device thatopens to atmospheric pressure without first causing the transientpressurized liquid to do work on the drive component.

FIG. 13 illustrates another embodiment of a transient pressure drivedevice in accordance with the present disclosure that can be operablewith the system of FIG. 1. As shown in FIG. 13, the transient pressuredrive device can comprise a bypass line 30 and a bypass valve 31associated with the bypass line. The bypass valve can be operablealternately to open to divert liquid from the drive component 15 a backto the liquid source 10, such as via conduits 14 and 12, and to close,thus blocking the bypass line, to initiate a high pressure transientpressure wave in the liquid in the drive conduit 11. In someembodiments, the valve 31 on the bypass line can be located at a tee inthe drive conduit at any point in the upstream two-thirds of its length.The drive conduit can be filled with liquid its entire length from thesource 10, or optional pump 18, to the drive component 15 a.

In operation, at first liquid can flow from the source 10 by gravity orpumping down the drive conduit to the bypass tee and valve where theflow exits the drive conduit into the bypass line and is returned to thesource by gravity or pumping. Meanwhile, the liquid in the remainder ofthe drive pipe downstream of the bypass tee to the drive device 15 a canbe at rest. Then the bypass valve can be quickly shut creating transientpressure waves in the drive conduit. Two one-half magnitude pressurewaves are generated, one that travels down the remaining drive conduitto drive component and one that travels back up the drive conduit towardthe source thereby pressurizing the entire drive line at one time oranother to one-half magnitude transient pressure. When the downstreampressure wave reaches drive component, if the drive component provides adead end or stationary load, the one-half magnitude pressure wave willdouble to full magnitude sending a full magnitude pressure wave back upthe drive conduit and exerting full magnitude pressure against the drivecomponent to do work. Other transients result in a water hammer-typefashion that do work against the drive component. When the transientpressures have been expended against the drive component, the bypassvalve is reopened so that flow begins again from the source through thedrive conduit and into the bypass line and the cycle repeats.

For a pump driven system, the greatest work efficiency can result if thebypass line is connected near the downstream end of the drive conduit atthe drive component. Also, for the protection of the pump from hightransient pressures, a surge tank, air chamber, pressure relief valvedischarging back to the source, or other such pressure dissipatingdevice can be included downstream of the pump to relieve pressure, storeor bypass liquid, and prevent high transient pressures from reaching anddamaging the pump.

For a gravity driven system, the greatest overall efficiency can resultwhen the bypass line is connected at a location along the drive conduitwhere the fall or elevation drop in the drive conduit is just enough tocause the desired liquid velocity out the bypass line and no more. Thatway the least friction and elevation or potential energy loss resultsfor the bypassed flow and for the pumping energy required to pump thebypassed flow back to the source. The drive conduit downstream of thebypass valve that is pressurized by the transient pressure caused by theclosing bypass valve can remain at the bypass elevation or can eitherdrop in elevation or rise in elevation depending upon the particularneed and application.

If the bypass line is located two thirds of the length of the pressuredrive conduit from the source to the pressure drive component, thepressure wave that travels to the pressure drive component will reflectat the device and travel back to the bypass location in the time ittakes the pressure wave that travels back up the conduit to reach thesource. The reflection wave from the source that then travels back downthe conduit will meet the wave reflected from the pressure drivecomponent at the one-third point on the conduit.

If the bypass line is located one third of the length of the pressuredrive conduit from the source to the pressure drive component, thepressure wave that travels down the conduit to the pressure drivecomponent can reflect at the device in the same amount of time that thepressure wave that travels back up the conduit takes to travel back tothe source and be reflected back down to the bypass line. The reflectionwave from the source that then continues to travel down the conduit andcan meet the wave reflected from the pressure drive device at thetwo-thirds point on the conduit.

Locating the bypass line at other locations along the drive conduit cancause similar but different timing of pressure wave reflections. In oneaspect, the location of the bypass line and the drive conduit length canbe selected so as to have the least loss of energy from bypassed liquidwhile pressurizing as much of the drive conduit length as possible withhigh transient pressures during each cycle.

In one aspect, an optional valve 32, such as a fast acting control orone-way valve, can be included in the pressure drive conduit justdownstream of the bypass line and bypass valve. The valve 32 canfunction automatically or can be controlled to open to admit liquid intothe downstream drive conduit when pressure is low in the downstreamconduit and to quickly close during high pressure waves so that as nearas possible the high pressure wave is doubled and reflected back downthe drive conduit to the pressure drive component.

With further reference to FIG. 1, in one aspect, the system 1 canprovide a renewable or in some aspects reusable energy cycle processthat can operate from many sources of heat energy whether that heatsource is solar rays, air, water, earth, geothermal, nuclear, fossilfuel, or any other heat source. Liquid from the liquid source 10 can bereleased or pumped into the drive conduit 11. The confined flowingliquid can be conveyed at a velocity in the drive conduit to thedownstream transient pressure drive device 15 where the liquid flowenters and passes through the transient pressure drive device component.This component can include any configuration and construction, such asthose described hereinabove, which can repeatedly produce liquidtransient high or low pressures in the liquid flow and cause thetransient pressures to drive the device 16. The drive device can bedirectly or indirectly connected in any manner to the transient pressuredrive device 15. The transient pressure drive device can produce theliquid transient high or low pressures by repeatedly stopping,substantially slowing, turning, or partially obstructing the liquid flowin any manner. Liquid flowing through and exiting the transient pressuredrive device can be conveyed by the conduit 14 to the heat source 13,which can be an active or passive temperature and heat maintenancecomponent. The liquid flow can then returned to the liquid source 10 orrouted directly to the drive conduit 11 by the conduit 12.

The heat source 13 can function to restore and maintain from thesurroundings or otherwise a consistent range of temperature and heatcontent of the liquid to achieve continuing and efficient work/energyproduction from the transient pressure drive device as the liquid coolsdown from doing work. In some embodiments, the heat source can comprisea heat exchanger. In other embodiments, the heat source can comprise aheater. In one aspect, one or more of the system components can beconstructed and/or operated for temperature and heat restoration andmaintenance from the surroundings so that a separate heat source may notbe required in some applications if sufficient temperature and heatmaintenance is achieved by the other components for consistent,efficient, and continuing operation. In another aspect, sufficientactive or passive heat transfer and temperature restoration can beaccomplished in the system components as a whole to restore and maintainconsistent work producing liquid temperatures and heat content as theliquid returns and flows into the drive conduit 11 and transientpressure drive device 15 components.

In one embodiment, the liquid return conduit 12 may be omitted if liquidconservation is not needed in a particular application. In this case,liquid flow can be conveyed as needed through the outflow conduit 14 tothe heat source 13, followed by being released to waste from the systemrather than being returned to the liquid source.

As work is done, internal molecular energy is extracted from the liquidand transferred through the pressure drive device to a work device 16that does useful work on things outside of the system such as generatingelectricity for use or operating any type of machinery. As each cycleextracts internal molecular energy from the liquid, the internal kineticenergy of the liquid molecules is correspondingly reduced. Sincetemperature is a measure of the internal kinetic energy of a liquid,that reduction in internal molecular kinetic energy is manifested in areduction or cooling in the temperature of the liquid.

Each cycle extracts an incremental amount of internal kinetic energyfrom the liquid and causes an incremental amount of additional cooling.If operated in perfect thermal isolation, the repetitive work cycleswould cause the liquid to cool down until it began to solidify as slushand the process would stop. However, in actual operation, heat energyfrom the surroundings (usually the air, but can be the earth, water oranything else with heat energy) can be passively or actively used totransfer heat energy back into the liquid and warm it back up after ithas been caused to do work.

The function of the heat source is to warm the liquid back up to itsoriginal temperature through heat exchange or any other means. The heatsource can thus restore the internal molecular energy content of theliquid and acts as the component that provides the outside energyrequired for continuing operation.

An example of a heat source is a tube and fin-type metal heat exchangerwhereas the liquid passes into the heat exchange the flow divides andpasses through a number of metal tubes that have a large number of finswith a large surface area. As the liquid passes through the tubes, airis caused to pass across the tubes and fins. The fins and tubes areheated by the air passing around them. In turn, the heated tubes andfins cause heating of the liquid passing through the heat exchangertubes. By the time, the liquid passes out of the heat exchanger, it hasbeen heated or warmed back up to its original operating temperature. Theinternal molecular kinetic energy of the liquid has thus been restoredand the liquid is thus ready to be used again in another transientpressure work process cycle.

The design and proper sizing of such a tube and fin-type heat exchangeris a well-known science and such heat exchangers are commonly designedand used in air conditioning systems, automobiles as radiators, andnumerous other applications. But, as an example, a heat exchanger thatcould function as the heat source for a transient pressure work processenergy system generating 18 KW of power, can comprise a 6-foot wide by5-foot tall, and 4-inch deep fin and tube type heat exchanger. The finsand tubes are arranged in similar fashion to that of an automobileradiator having a total fin and tube area of 2,167 square feet. A fan isused to continuously blow fresh or new air through the exchanger toaccomplish the transfer of heat from the air into the liquid flowing inthe tubes of the heat exchanger.

Thus, the heat source, which can comprise of a heat exchanger, areservoir, or a length of conduit, or any other such suitable design,functions to restore the internal molecular kinetic energy of the liquidmolecules to their original energy level and temperature after beingcaused to cool down in the work process. That restoration of theinternal kinetic energy of the liquid molecules ensures that continuingwork can be done by the repetitive transient pressure cycle and process.In that manner, sufficient molecular kinetic energy can be harnessed tocause the system to be self-operating extracting heat from the air orother surroundings and transferring that heat into the process liquidand then causing elastic reactions in the restored internal molecularkinetic of the liquid molecules that cause repeating high transientpressures that can be caused to do work.

In one aspect, two keys to a successful continuing process are: 1) toavoid relieving the elastic pressure energy available in the repeatinghigh transient pressures without first making those transient pressuresdo work as they are released and relieved, and 2) to reduce the frictionand pipe flexure losses during the repetitive water hammer type cycle.For example, the stronger and more rigid the materials of the pressuredrive conduit and pressure drive device, the greater the availablepressure energy, because the rigidity of the materials preventsrelieving the transient pressure through flexure of the conduit anddevice walls. Also, expansion of the liquid into an air chamber, a lowpressure liquid source, a larger diameter conduit, or to atmosphericpressure relieves part or all of the transient pressure without doingwork.

As for the proper length of the drive conduit, traditional ram pumpdesign has held one or more of several empirical relationships relatingthe drive pipe length either to the drive bead or fall in the drive pipeor the length divided by the diameter of the drive pipe. However,research and analysis by Young, in his paper “Simplified Analysis andDesign of the Hydraulic Ram Pump” (Proceedings of the Institution ofMechanical Engineers, Part A: Journal of Power and Energy, 1996,210:295) determined that these empirical relations actually have littleto do with how to determine the proper length of a drive pipe. Hepointed out that Azoury, Baasri, and Najm in their paper “On the OptimumUtilisation of Water Hammer” (Proceedings of the Institution ofMechanical Engineers, Part A Journal of Power and Energy, 1988,202(A4):249-256) had indicated the minimum drive pipe length isdetermined by how fast the waste valve closes. They indicated the drivepipe length needs to be at least sufficient so that the closing valvecompletely closes before the first returning transient pressure wave hastime to return down the drive pipe back to the valve. Young then derivesand proposes an equation for determining maximum drive pipe length for asteel pipe as:

Lmax=110HD

where

-   -   Lmax:=maximum drive pipe length (in meters)    -   H=head on the drive pipe at the waste valve (in meters)    -   D=drive pipe diameter (in meters)

That equation can be used to determine a maximum drive pipe length.However, finding the optimum drive pipe length involves the balancing ofthe friction and other energy losses in the drive pipe against theenergy used in operating the valves and against the frequency of valvecausing wear and tear on the valve. The speed of the valve closuredetermines the minimum length of the drive pipe. Any longer drive piperesults in more friction and other energy losses. So, the drive pipeshould be as short as possible based on the speed of the valve. But, onthe other hand, a shorter drive pipe requires many more valve movementsper second or minute than a longer drive pipe. Thus, the drive pipelength is determined by balancing drive pipe friction and other energylosses against the energy consumption of valve operation, the requiredspeed and frequency of their operation, and the resulting wear and tearof operation.

As discussed above, work and heat are processes by which energy can betransferred in and out of a system of mass, and energy, like mass, canbe neither created or destroyed but is transferred either by work orheat processes. As also discussed above, the source of the energy in atransient pressure work process is the internal molecular energy of theliquid. So, a transient pressure work process converts molecularinternal energy of a liquid into pressure energy, which pressure energydoes work upon the device or object being driven by the transientpressure work process. In that work process, a net transfer of internalenergy out of the liquid occurs. Accordingly, the temperature of theliquid must decrease.

If the process is repeated in another transient pressure cycle, thetemperature of the liquid again decreases. Assuming no heat istransferred into the liquid, the result can be a cooling of the liquiduntil it begins to freeze and stop functioning as a liquid. However,that situation can be avoided with the present system. Here, energy isadded to the liquid through the heat transfer process in the heatsource.

Thus, in some embodiments, the system can operate from any consistentsource of heat energy for the heat source that can restore and maintainoperating temperatures for the liquid and the transient pressure drivedevice. One source of heat is solar energy stored as heat energy in theair, the earth, or in natural bodies of water. Unlike many solar energyprocesses, the present system need not operate directly from theshort-wave solar radiation of the sun. Instead, the heat source of thepresent system can indirectly operate from the energy of the sun byusing solar energy captured and stored in things warmed directly orindirectly by the sun, such as air, water, or the soils of the earth.

The present system can thus harness energy from the sun for continuouslydoing any type of useful work including generating electricity, drivingmechanical devices, or doing any other type of useful work. The systemcan therefore be versatile because it can operate and do work mostanywhere on earth at most any natural air, water, or earth temperaturefrom 60 degrees below zero Fahrenheit and below to 125 degrees above solong as a liquid is used that does not freeze or vaporize in the neededoperating temperature. All substances above absolute zero (−273° C.),which is basically everything on earth, have stored solar heat energyand thus are capable of use as a source of heat in the present system asthey are reheated directly or indirectly by the sun.

Thus, in some embodiments, the present system can operate at or belowthe ambient temperature of the air, water, soil, or other substance usedas the heat source. The energy cycle accesses the internal energy of aliquid to do work without having to heat the liquid up first. Rather,the energy cycle begins at whatever temperature state the liquid is inand then causes the liquid to cool down as work is done. The temperatureof the cooled liquid can be restored to any desired temperature throughheat exchange with any suitable heat energy source. As a result, anyamount of cooling in one or more work cycles or events can be allowed tooccur prior to restoring the liquid temperature so long as the liquiddoes not begin to freeze or transition to a solid state. The presentsystem can therefore be versatile and can operate in any temperaturerange for any mass in its liquid state.

In one aspect, the present system can be operated so that there is nowaste stream of any kind whether liquid, gas, particulate, or othersolid. Rather, there is only transformation of liquid internal molecularenergy into liquid pressure energy, transfer of energy out of the liquidby doing work, and transfer of energy back into the liquid by heat.

In another aspect, an initial amount of outside energy may be suppliedto the system in order to begin operation of the system. Once operatingproperly, however, the energy cycle can sustain itself in whole or inpart and produce an amount of useful work within the physical limits ofthe energy that can be stored in the liquid, the energy that can betransferred out of the liquid by doing work, and the energy that can betransferred back into the liquid by the heating process.

The Energy Source and Application of Thermodynamic Principles

As discussed hereinabove, the analysis of ram pump system efficiencieshas shown that transient pressure waves are caused by elastic reactionscaused by internal molecular kinetic energy of liquids. These internalelastic reactions create transient pressures that can be used to do workin repetitive water hammer type cycles. But, energy, like mass, can beneither created nor destroyed. Energy can be stored in a mass, or can betransferred in or out of the mass either by work or heat processes. But,it cannot be created. Work done by transient pressure processes transferenergy out of the liquid mass. Mathematically, the First Law ofThermodynamics states:

E−E ₂ =Q−W

where

-   -   E₁=initial internal energy    -   E₂=final internal energy    -   Q=heat transfer    -   W=work done on system (becomes positive when work is done by the        system)

The law thus requires that the energy of a system must decrease whenwork is extracted from it unless an equal amount of heat is added at thesame time. It can be shown that in a transient pressure work process, aswork is extracted from the internal elastic energy of the liquid, theinternal energy decrease is manifested as a temperature decrease.

The internal energy of a liquid encompasses all molecular energy of theliquid. But, for transient pressure processes, the attraction energy andthe translational kinetic energy of the moving liquid molecules are theimportant portions of the total molecular internal energy. It is thetranslational kinetic energy that reacts to create high transientpressures while it is the attraction forces that constrain liquidexpansion to a particular volume. Because the remaining internal energydoes not appear to act in transient pressure processes, the remaininginternal energy can be dropped from further consideration. So, E₁ and E₂as considered here refer only to that part of internal molecular energy,chiefly the translational kinetic energy, that reacts in the transientpressure process.

Further, it is useful to limit the energy system to be analyzed to theconfined liquid itself. Energy inputs and outputs from the liquid willbe analyzed. First, transient pressure processes are pressure impulseprocesses that happen so rapidly in the drive conduit and the pressuredrive device that there is essentially no time for energy to transferinto the liquid as heat. Thus, the heat transfer term, Q, in the energyequation for the transient pressure processes in the drive pipe andpressure drive device is essentially zero and can also be dropped fromthe energy equation.

While, the work done in the transient pressure process is important. Ina simple water hammer process, the work done by the liquid is limited tothe non-useful work done on the pipe and any fittings or valves in therapid back and forth pressure wave and liquid flow movements of thetransient pressure waves. But, that water hammer process can be used torepeatedly pump water or repeatedly do work on a mechanical device. Sucha work process results in work done by the liquid. So, the work term ofthe energy equation is positive.

Thus, dropping the heat term from the equation as insignificant, makingwork positive, and rearranging, the energy equation becomes simply:

W=E ₁ −E ₂

In other words, the First Law of Thermodynamics, as applied to atransient pressure work process, requires that the work done by theliquid must result in a decrease in the internal energy of the liquid.That this decrease in internal energy necessarily manifests itself as adecrease in temperature is discussed next.

As noted above, the two internal molecular energy forces that react in atransient pressure process are the kinetic translational energy of theliquid molecules and the attractive forces exerted by the molecules uponeach other.

First, the translational kinetic energy within a confined liquid, KE,can be expressed in terms of the average kinetic energy of all of themolecules of the liquid as follows:

KE=½m ν ²

where

-   -   m=combined mass of all liquid molecules in the liquid volume    -   ν=average random translational velocity of all liquid molecules        in the volume

It is well understood that the pressure of a liquid is directly relatedto the kinetic energy, KE=½mν². When something acts to confine therandom movement of liquid molecules into a smaller space than what theirkinetic energy would otherwise allow them to move, the kinetic energy ofthe randomly moving molecules causes them to bounce into each other withgreater force. That collective momentum force of the millions ofmolecules striking each other and the walls of a container is calledpressure. In English units, pressure has units of pounds of force perunit area such as pounds per square inch (lbs/in² or psi) or pounds persquare foot (lbs/ft² or psf). The closer liquid molecules are forcedtogether, the harder they bounce off the walls of a container and eachother and the greater the pressure force. And the opposite is true, asthe liquid molecules are given more volume and space to move in, thelesser the pressure force.

In a confined liquid, pressure is thus a type of direct measurement ofthe average internal kinetic energy of the liquid, E=½mν² and resultsfrom the collective momentum force of the random kinetic movement of theindividual liquid molecules. It is this internal molecular translationalkinetic energy that reacts and causes transient pressures when themolecules are forced closer together by their momentum or by othermeans. It is thus, this translational kinetic energy that by the FirstLaw of Thermodynamics must decrease when work is done in a transientpressure process. It cannot be the attractive forces between themolecules, because those forces act toward keeping the molecules closetogether. Because it is the translational kinetic energy that providesthe pressure to do work, it must be the internal translational kineticenergy that must decrease. The energy equation for the work process isthus written:

W=E ₁ −E ₂ =KE ₁ −KE ₂=½mν ₁ ²−½mν ₂ ² or W=½m(ν₁ ²−ν₂ ²)

Thus, the energy source for the work done by the liquid in a transientpressure process on its surroundings is the internal randomtranslational kinetic energy of the liquid molecules. As the work isdone, part of that energy is transferred from the liquid molecules tothe device driven. That energy transfer causes a decrease in the averageinternal translational kinetic energy of the molecules and a reductionin the average random translational velocity of the liquid molecules bythe amount ν₁−ν₂. That this decrease in internal translational kineticenergy in the liquid necessarily results in a decrease in thetemperature of the liquid is next shown.

Temperature is a direct measure of the kinetic energy, KE=½mν² of aliquid or gas. For example, a common measuring device for temperature isa liquid thermometer. A liquid thermometer measures the change in volumeof the liquid within the thermometer when exposed to a hot or coldsubstance. When exposed to a hot substance, heat transfers from thesubstance into the liquid within the thermometer. That heat energytransfer increases the kinetic energy of the thermometer liquidmolecules. The randomly moving liquid molecules then have more kineticenergy to overcome the attractive forces that hold them together. Thatincreased energy allows the randomly moving liquid molecules in thethermometer to bounce and become farther apart. That greater movement ofthe molecules causes the liquid volume to increase. And, that volumeincrease is seen in the thermometer tube as a rise in the liquid columngiving a higher temperature reading.

The opposite is true when the thermometer is exposed to a coldsubstance. The heat energy transfer from the thermometer into the coldsubstance causes the liquid molecules in the thermometer tube to losekinetic energy. That loss allows the attractive forces between themolecules to pull the molecules closer together. The thermometer liquidcontracts and causes a shortening of the liquid column. A coldertemperature reading is the result.

Thus, what is important here is to understand that temperature andpressure are measures of, and result from, the same thing—internalkinetic energy of the liquid molecules. When that internal molecularkinetic energy changes the two measures of that internal kinetic energy,temperature and pressure, change accordingly. An increase in internalmolecular kinetic energy increases temperature and pressure. Likewise adecrease in internal molecular kinetic energy decreases temperature andpressure.

Finally, if the liquid is caused to do work by harnessing its internalmolecular kinetic pressure energy force in a liquid transient workprocess, as shown above the First Law of Thermodynamics holds that workenergy transfer of necessity decreases the molecular kinetic energy ofthe liquid molecules. That loss of molecular kinetic energy causes themolecules to come closer together, and so, the temperature, which is ameasure of that collective distance between molecules, decreasesaccordingly.

The result of the work process is thus equivalent to that which occurswith a loss of molecular kinetic energy through the cooling heattransfer process. That fact means that the liquid literally cools intemperature as work energy is extracted from the molecular kinetic, ormomentum forces, of the liquid molecules. This fact is extremelyimportant because it is that cooling of the liquid as work is extractedfrom the liquid in a transient pressure work process that makes itpossible to add energy back into the liquid through simple heatexchange.

The change in temperature of the liquid to its final state of kineticenergy can be determined from the specific heat (or heat capacity perunit mass) property of the liquid, usually denoted with the symbol c,but here denoted as s. The well-known equation relating the specificheat of a liquid to its change in temperature is:

${\Delta \; T} = \frac{Q}{m*s}$ $\begin{matrix}{{{where}\mspace{14mu} \Delta \; T} = {{change}\mspace{14mu} {in}\mspace{14mu} {temperature}}} \\{Q = {{the}\mspace{14mu} {heat}\mspace{14mu} {or}\mspace{14mu} {kinetic}\mspace{14mu} {energy}\mspace{14mu} {loss}\mspace{14mu} {from}\mspace{14mu} {the}\mspace{14mu} {work}\mspace{14mu} {done}}} \\{m = {{mass}\mspace{14mu} {of}\mspace{14mu} {the}\mspace{14mu} {liquid}}} \\{{s = {{specific}\mspace{14mu} {heat}\mspace{14mu} {of}\mspace{14mu} {the}\mspace{14mu} {liquid}}}\;} \\{{{for}\mspace{14mu} {water}} = {1.0\mspace{14mu} {cal}\text{/}{g\mspace{11mu}}^{{^\circ}}{C.\mspace{11mu} {at}}\mspace{14mu} 25^{{^\circ}}\mspace{11mu} {C.\mspace{11mu} {or}}\mspace{14mu} 1\mspace{14mu} {Btu}\text{/}{{lbm}\mspace{11mu}}^{{^\circ}}{F.}}} \\{= {778.169262\mspace{20mu} {ft}\text{-}{lbs}\text{/}{{lbm}\mspace{11mu}}^{{^\circ}}{F.}}}\end{matrix}$

Here, energy is extracted from the liquid by doing work. As just notedabove, the results of a transient pressure work process is theequivalent of extracting heat energy (as measured by temperature) fromthe liquid. So, the equation can be written:

$\mspace{20mu} {{{- \Delta}\; T} = \frac{W}{m*s}}$ $\begin{matrix}{{{where}\mspace{14mu} \Delta \; T} = {{change}\mspace{14mu} {in}\mspace{14mu} {temperature}}} \\{W = {{the}\mspace{14mu} {work}\mspace{14mu} {done}\mspace{14mu} {by}\mspace{14mu} {the}\mspace{14mu} {liquid}\mspace{14mu} {in}\mspace{14mu} {the}\mspace{14mu} {transient}\mspace{14mu} {work}\mspace{11mu} {process}}} \\{m = {{mass}\mspace{14mu} {of}\mspace{14mu} {the}\mspace{14mu} {liquid}}} \\{{s = {{specific}\mspace{14mu} {heat}\mspace{14mu} {of}\mspace{14mu} {the}\mspace{14mu} {liquid}}}\;} \\{{{for}\mspace{14mu} {water}} = {1.0\mspace{14mu} {cal}\text{/}{g\mspace{11mu}}^{{^\circ}}{C.\mspace{11mu} {at}}\mspace{14mu} 25^{{^\circ}}\mspace{11mu} {C.\mspace{11mu} {or}}\mspace{14mu} 1\mspace{14mu} {Btu}\text{/}{{lbm}\mspace{11mu}}^{{^\circ}}{F.}}} \\{= {778.169\mspace{20mu} {ft}\text{-}{lbs}\text{/}{{lbm}\;}^{{^\circ}}{F.}}} \\{= {389.084631\mspace{20mu} {ft}\text{-}{lbs}\text{/}{{cup}\mspace{11mu}}^{{^\circ}}{F.}}}\end{matrix}$

The negative sign used in the equation denotes a decrease intemperature. The following table provides perspective for the potentialwork energy available in the internal molecular energy of a volume ofwater molecules. The table assumes a repetitive transient work processcycle that occurs at the rate of one work process cycle per second,which for circular motion is 60 rpm. The power available for varioustemperature changes or decreases is thereby computed as follows:

Temperature Change Volume of Water 1° F. 5° F. 10° F. 1 cup 0.71 hp 3.53hp 7.10 hp 1 quart 1.42 hp 7.10 hp 14.2 hp 1 gallon 5.68 hp 28.4 hp 56.8hp 1 cubic foot (ft³) 42.5 hp  212 hp  425 hp

In a ram pump process, the temperature reduction in the liquid is slightand does not matter because the water is sent on to use as a watersupply. But, for a system that returns the liquid to the source to domore work, the work energy extracted from the liquid must bereplenished. Without that replenishment, if the work process is repeatedin another transient pressure cycle, the temperature of the liquid againdecreases. Taken to the extreme, and assuming no heat is transferredinto the liquid, the result would be a repeated cooling of the liquiduntil it began to freeze and turn to slush. In that state, transientpressures could no longer be produced and the work process would stop.

However, since the extraction of the work energy from the liquidmanifests itself as a cooling in temperature or temperature reduction,another law of thermodynamics can be used to replenish the energy inliquid that is to be returned to the source, recycled and reused in aliquid transient pressure work process. That law holds that when twobodies of mass of different temperatures are placed in contact with eachother, heat transfer will occur from the mass with the highertemperature to the mass with the lower temperature until thetemperatures of both masses become equal.

So, what can be done to replenish the energy extracted from the liquidin a transient pressure work process is to expose the liquid to a warmermass that can warm the liquid back up after its use in the process. Thatwarmer mass can be air, earth, water, or anything else with sufficientheat energy to warm the liquid back to its original temperature. Theheat transfer can be accomplished with any heat exchanger of sufficientsize and surface area and liquid transit or exposure time to accomplishthe required heat transfer of energy from the air, earth, water, orother mass into liquid.

The design of heat exchangers is a well-known science. Heat exchangersare commonly used in air conditioning systems, refrigerators, inautomobiles as radiators and the like to transfer heat from a liquidinto the air. They can also be used to transfer heat from the air intothe liquid. Such fin and tube-type heat exchangers are common, but manyother types and means for temperature and heat exchange exist. Anydevice or process that can accomplish the required heat exchange can beused.

Here, a fin and tube-type heat exchanger will be used as an example. Aspresented above, water has a sufficiently high specific heat capacity todo a significant amount of work from a reasonable temperature change orreduction. For example, a transient pressure work process having a flowrate of 3.0 feet per second in a 3-inch pipe or 0.147 ft³/s, hassufficient internal energy to produce 18 KW of power or electricalenergy with a temperature drop or reduction of 1.0 degree Celsius or 1.9degrees Fahrenheit.

Thus, in a transient pressure work process with water flowing at a netflow rate of 0.147 ft³/s from the liquid source at a temperature of 70degrees Fahrenheit (21.1 degrees Celsius) through the drive conduit andpressure drive device, where transient pressures are produced and usedto extract 18 KW of power and work energy from the internal energy ofthe liquid, will discharge from the pressure drive device at 68.1degrees Fahrenheit (20.1 degrees Celsius).

Before being returned to the liquid source, the 0.147 ft³/s of cooleddown liquid flow, is passed through a fin and tube-type heat exchangerwith sufficient capacity to use air at 70 degrees Fahrenheit (21.1degrees C.) to warm the 68.1 degree Fahrenheit (20.1 degrees C.) liquidback up to the original liquid source/operating temperature of 70degrees Fahrenheit. The mass flow rate of the water is 4.15 kg/s. Thespecific heat of the water is 4181 J/kgK, the specific heat of the airis 1006.8 J/kgK, the air density at sea level is 1.1614 kg/m³, and therequired heat transfer rate is 18,000 W. Using these values and theprinciples of conservation of energy, an air mass flow rate of 5 kg/swill heat the water passing through the air exchanger back up to 70degrees Fahrenheit while the air passing through and against the finsand tubes of the heat exchanger will cool down by 4.6 degrees Fahrenheit(3.6 degrees C.). The volumetric flow rate of the air would need to be4.31 m³/s.

Using a conservative overall heat transfer coefficient of 25 W/m²K, therequired area of the heat exchanger fins is 2167.4 ft². That heatexchanger area can be compactly provided in the relatively closelypacked radiator style fin and tube-type design commonly used inautomobile radiators such that the heat exchanger could be about 6.0feet wide and 5.0 feet high with a 4-inch depth. At that size, thevelocity of the air coming into the heat exchanger would need to be 4.3ft/s, or about 3 miles per hour, which is a reasonable air velocity forpractical operation.

After passing through the heat exchanger, the now 70 degree Fahrenheittemperature liquid would be returned to the liquid source with itsinternal energy replenished and ready to be used again in the transientpressure work process.

Energy Analysis for Complete Operation of a Transient Pressure WorkProcess and System

The above shows where the energy comes from to operate a continuoustransient pressure work process. It comes from the internal kineticmolecular energy of the liquid. What remains is to show that sufficientenergy can be extracted from the elastic reactions of the liquid in thetransient pressure work process to not only sustain its continuousoperation, but produce energy for uses outside of the system as well.That fact can be shown from an energy balance. It will be done for the18 KW transient pressure work process used as an example for the heatexchanger analysis above. But, first the total available transientpressure energy needs to be established.

Total Available Elastic Energy

The total molecular elastic energy created in the drive pipe when theliquid is first stopped by a fast acting valve can be determined fromNewton's Second Law: F t=m v, where F=force exerted by the stoppedliquid, t=time required for the liquid column to come to rest, m=mass ofthe liquid column stopped in the drive conduit, and v=the originalvelocity of the liquid column immediately before being stopped. Theforce is equal to the pressure multiplied by the valve area and the massis equal the unit mass of the liquid multiplied by the volume so that:

F t=mv  (15)

P A t=ρ A L v,  (16)

where P=pressure/unit area, A=area of the valve, ρ=unit mass, L=Lengthof the liquid column and A L=the volume of the liquid column. Thepressure wave caused by the stopping liquid travels up the drive conduitat the speed of a pressure or sound wave, known as the wave celerity,c_(p). At any time t the length of the column that has come to rest canthus be determined by L=c_(p) t. Rearranging t=L/c_(p) and substitutingthis relation into (16), the equation becomes:

$\begin{matrix}{{\frac{P\; A\; L}{c_{p}} = {\rho \; A\; L\; v}},} & (17)\end{matrix}$

then rearranging gives:

P A L=ρ A L v c _(p)  (18)

Equation (18) is in units of energy (foot-lbs, N·m, or Joules) with theleft hand side representing the pressure-volume energy relation familiarwhen working with gases since A L equals the volume of the liquidcolumn. But, here the right hand side of the equation represents themomentum energy, m v c_(p). In concise form, the equation can be writtenas:

P V=m v c _(p)  (19)

Equation (19) has a striking resemblance to the energy equation forideal gases, P V=nRT. That equation expresses the total amount ofpressure energy stored in a gas at any pressure and volume. Whereas,equations (18) and (19) express the total amount of pressure energystored in a confined liquid at rest at any pressure and volume (P V), orthe total amount of momentum energy of a moving confined liquid (m vc_(p)). Bringing that liquid column quickly to rest will cause pressureenergy of the magnitude: P V. While quickly releasing that confinedliquid, will create momentum energy in the liquid column of magnitude: mv c_(p).

Equations (18) and (19) have units of energy (foot-lbs, N·m, or Joules).The left hand side of equation (19) (P V) represents the pressure-volumeenergy while the right hand side of the equation represents the momentumenergy (m v c_(p)). The equation shows that the total amount of pressureenergy stored in a confined liquid at rest at any pressure and volume (PV) can be converted to momentum energy in a moving confined liquidcolumn (m v c_(p)) and vice versa. Bringing the liquid column quickly torest converts the momentum energy of the liquid column into pressureenergy of the magnitude: P V. While quickly releasing that confinedliquid, converts the P V energy into momentum energy in the liquidcolumn of magnitude: m v c_(p).

The equation can be used to determine the total energy available in aliquid transient process. The equation shows that a very large amount ofpotential energy is stored in any confined column of liquid underpressure. For example, a 20-foot long section of 3-inch (0.25 foot)diameter conduit filled with liquid at just 100 psi pressure haspotential energy at rest of P V=P A L=100×144×π×(0.25)²/4×20=14,137ft-lbs of energy. If pressurized and released at the rate of one cycleper one second or 60 cycles per minute (a common ram pump cycle time,which requires time for hydraulic recoil and opening of the waste valve,not needed here with an electrically operated valve) that energy has a25.7 horsepower or 19.67 KW power potential.

In a water hammer process, that 14,137 ft-lbs of energy is what causesthe water hammer. The repetitive hammer of the progressively smallerpressure waves move rapidly back and forth at the speed of sound (thecelerity, c_(p)) through the length of the 20-foot pipe until the 14,137ft-lbs of energy has been dissipated by friction and other losses. But,that repetitive hammer can be harnessed so that much of the 14,137ft-lbs of energy is made to do work. It is generally the repetitivenature of the water or liquid hammer that makes it possible to extractmore work from the transient pressure energy than it takes to create orcause it.

Application to an Example Transient Pressure Work System

An example transient pressure work process is illustrated in FIG. 14,and comprises elements of the system described hereinabove with theaddition of sudden reductions and a resonance chamber. A 40-foot longupstream section of 3-inch diameter galvanized steel drive pipe isconnected on its downstream end to a 2-foot long 12-inch diametergalvanized steel pipe that functions as a resonance chamber. A 20-footlong downstream section of 3-inch diameter galvanized steel drive pipeis connected to other end of the resonance chamber/pipe through a 3-inchdiameter electrically operated control valve.

At the upstream end of the upstream drive pipe, is connected a 3-inchdiameter galvanized steel pressurization tee with an electricallyoperated ½-inch pressurization valve connected into the system on the90-degree bend side of the tee. On the straight through side of the teeis connected a 1-inch diameter electrically operated control valve thatacts as a sudden drive pipe reduction as well as a control valve. The1-inch control valve in turn connects the pressurization tee and drivepipe assembly to a low pressure liquid source reservoir containingliquid at a temperature of 70 degrees Fahrenheit.

At the downstream end of the drive pipes is connected a 3-inch automatichydraulic pressure controlled check valve that connects the drive pipesto a transient pressure drive device. The transient pressure drivedevice includes a 3-inch tee connected to the drive pipes on theupstream side through the automatic check valve. A 3-inch electricallycontrolled waste valve is connected to the downstream side of the teewhile the 90-degree bend side of the tee is connected through a suddenenlargement to a 6-inch cylinder and piston assembly. In turn the pistonis connected through a piston rod to any generating device that cangenerate 18 KW of electrical power from the reciprocating action of thepiston. The waste control valve in turn is connected on its downstreamside to the heat exchanger described in detail above and designed for 18KW of heat transfer from moving air. The heat exchanger is in turnconnected to the liquid source to complete the transient pressure workprocess loop.

Finally, a pressurization pump is connected to the reservoir through aseparate ½-inch pipe and to the ½ inch pressurization valve on theupstream end of the drive pipes.

An energy analysis of a system in accordance with the present disclosureis set for the hereinafter. All valves begin in the closed position andall pipes, the pressure drive device, and the heat exchanger are filledwith water with all air removed. As the work process begins, thepressurization pump operates to provide 400 psi pressurized liquid intothe ½ inch pressurized water supply line while the ½-inch pressurizationvalve opens to admit the pressurized liquid into the upstream 40-footsection of drive pipe. When the upstream section of drive pipe ispressurized to 400 psi, the ½-inch pressurization valve closes.

The energy required for this pressurization process includes the energyrequired to operate the pump and provide 400 psi liquid through theshort ½-inch pressurization pipe and valve into the upstream drive pipesection and the energy required to operate the ½-inch electricallyoperated pressurization control valve. The distance the water moves inthe drive pipe during the compression or pressurization by the pump canbe computed from the bulk modulus of elasticity of water (about 300,000psi) with the result increased slightly to account for the elasticity ofthe steel pipe. A sufficiently accurate approximation for this increaseis to multiply the length computed from the bulk modulus of water by theratio of the wave celerity of water (4,720 ft/s) divided by the wavecelerity in the pipe (4,590 ft/s). The distance the water moves in the3-inch pipe to pressurize the 12-inch resonance chamber is:

$\begin{matrix}{{Length} = {{Ac}\text{/}{Ap} \times P\text{/}B \times L \times 4720\text{/}4590}} \\{= {0.785\text{/}{.049} \times 400\text{/}300,000 \times 2 \times 4720\text{/}4590}} \\{= {0.044\mspace{14mu} {ft}}}\end{matrix}$

The distance computation for the 40-ft length of pipe upstream pipe is:

Length=P/B×L×4720/4590=400/300,000×40×4720/4590=0.055 ft

So, the total force distance, d, in the 3-inch pipe is:0.044+0.055=0.099 ft.

The work done or energy used to pressurize the upstream drive pipe canbe computed from the well-known equation: W=F×d where F=force andd=distance. The force is the pressure, P=400 psi times, area for a3-inch diameter pipe is A=7.069 in². A 50 percent efficiency for thepump providing the pressure force is assumed. The work done on theliquid to pressurize the liquid to 400 psi is computed:

W=F/e×d=400/0.5×7.069×0.099=559.8 ft-lbs

The friction and minor losses in the ½-inch pipe are minimal because thepipe is short, but a conservative maximum of 1 psi (2.31 ft) pressureloss will be used here. Thus, the pump must provide 401 psi water at thepump. The maximum 1 psi pressure energy loss incurred in moving thewater column in the 3-inch pipe by 0.099 ft is:

W=A L γ h/e=0.099×0.049×62.4×2.31/0.5=1.4 ft-lbs

The energy required to operate the ½-inch valve which can beaccomplished with 10 watts or less of energy or 7.4 ft-lbs. The totalenergy used to pressurize the 40-foot section of upstream drive pipe andthe resonance chamber is therefore less than 570 ft-lbs.

In contrast, the energy then made available in the 40-foot pressurizedsection of 3-inch pipe and 2-foot long resonance chamber for doing workis computed as:

Energy=P V=400×144×(π×(0.25)²/4×40+2.0×π×(1.0)²/4)=203,575 ft-lbs

The difference in energy expended to pressurize the system versus thepotential made available energy is more than 203,005 ft-lbs. Of coursenot all this available energy can be harnessed, the moment any of thispressure is relieved that part of the energy not made to do work willimmediately revert back to unusable internal energy. But, thecomputation shows that there is over fifteen times more potential energyavailable to produce the needed 18 KW or 13,275 ft-lbs/s when the workprocess cycle is repeated once every second.

So, to extract 13,275 ft-lbs of energy every second from this 203,575ft-lbs of available energy each second, an operation cycle is repeatedonce every second. The control valve that separates the upstream drivepipe and resonance chamber from the downstream drive pipe section isquickly opened. That valve action quickly releases the pressure into the20-foot downstream drive pipe section and causes transient pressurewaves that travel repeatedly at the speed of sound through both pipesand the resonance chamber rapidly dropping in pressure as work is donein driving the piston and energy is lost in friction and other losses.

The piston is driven in an automatic hydraulic jack like fashion. Theupstream drive pressure is shot down the downstream drive pipe and slamsinto the piston. The impulse impact causes the piston to be drivenupward while low pressure at the upstream end of the drive pipes, causesliquid to be drawn into the pipes from the liquid source through theopen 1-inch control valve at the liquid source. Any time the reactiontries to reverse, the upstream 1-inch control valve slams shut stoppingany backward flow just as in any simple hydraulic jack operation, butvery quickly so that high pressure transient waves are reflected backdown the pipe to drive the piston. The 1-inch control valve thus opensduring low pressure waves to admit liquid into the pipes and then slamsshut to stop and reflect high transient pressure waves back down thepipe to drive the piston.

The 6-inch piston is initially in position sufficiently close to theface of the sudden cylinder enlargement at the 3-inch tee into the6-inch cylinder so that no appreciable pressure loss results from thesudden enlargement. So, the first impact of the initial 400 psi pressurewave doubles as it slams into the piston cylinder and exerts over 22,600lbs of thrust against the piston. That initial thrust begins the drivingof the piston. Meanwhile rapid back and forth pressure wave cycles occurin the resonance chamber as the pressure begins to be relieved causingvery rapidly repeated and increased pressure waves to be transmittedinto the downstream drive pipe to drive the piston. The upstream drivepipe provides the liquid needed into the resonance chamber and adds tothe driving pressure forces exiting the resonance chamber toward thepiston as high transient pressure waves travel up and down the upstreamdrive pipe.

As the piston is driven, all pressures begin to drop until the pressurewaves become sufficiently dissipated to no longer be able to drive thepiston. At that point, the waste valve is opened. The remainingpressures that cannot drive the piston cause the liquid to be expelledfrom the cylinder, through the waste valve, through the downstream heatexchanger and back to the liquid source.

As the liquid is expelled from the cylinder, the direction of the pistonreverses and the piston is returned to its initial position ready to bedriven again in the next transient pressure work cycle. All valves arethen closed and the cycle is repeated.

The energy used to operate the pressure drive part of the cycle includesthe energy required to operate the three valves, the upstream 1-inchcontrol valve at the source reservoir, the 3-inch control valve betweenthe upstream and downstream portions of the drive pipe, and the 3-inchwaste valve. Those valves can be operated using less than 150 watts ofenergy. Because the remaining unused pressure not able to drive thepiston is available and used to cause the liquid flow from the cylinderthrough the waste valve, through the heat exchanger, and back into theliquid source, no other energy input is required for accomplishing thisreturn flow.

The net result is that it has been shown that more than enough work canbe done to produce 18 KW or 13,275 ft-lbs of work-load energy from eachtransient pressure cycle each second. In fact, in this design, it hasbeen shown that there is much more than enough repeated transientpressure energy available for the work process than is actually neededto drive the 18 KW load on the piston. Whatever, work is not done by thetransient pressures is immediately converted back to internal energy themoment the transient pressures are relieved. So, there is actually noexcess work done, but only that required to drive the 18 KW load on thepiston and to return the liquid through the heat exchanger back to theliquid source.

Thus, the energy entering and exiting the pressure drive devicenaturally balances with the amount of work extracted from the transientpressure drive process being equal to the drop in internal energy andtemperature in the liquid as it is expelled from the drive cylinderthrough the waste valve.

It takes comparatively little energy to cause the flow through the heatexchanger and the return of the liquid to the source, so the energydeficit in the liquid, or reduction in overall energy as the liquidflows into the heat exchanger, is essentially 18 KW. That energy deficithas caused the liquid to cool by 1.9 degrees Fahrenheit (1.0 degreeCelsius). The heat exchanger adds 18 KW of energy back into the liquidby heating the liquid back up to its original temperature of 70 degreesFahrenheit. That heating is accomplished from 70 degree air energy blownthrough the heat exchanger.

The example heat exchanger discussed above is designed for that purpose.That heat exchanger is actually a little larger than required toaccomplish 18 KW of heat transfer from 70 degree Fahrenheit air. So,with the exception of the small amount of energy required for the airfan that is needed to blow air through the heat exchanger at 4.3 feetper sec or 3 miles per hour, the energy balance nearly completes withthe heat exchanger transferring 18 KW of heat energy back into theliquid. That heat transfer restores the internal molecular kineticenergy of the liquid to its original state so that the liquid can bereturned to the source and continuously reused in subsequent transientpressure cycles.

To finish the energy balance, the energy required to operate the 1-inchcontrol valve, the two 3-inch control valves, the ½-inch pressurizationvalve, the air fan on the heat exchanger and the pressurization pump issupplied from the 18 KW generator driven by the transient pressure drivepiston and rod assembly. As discussed above, that energy is less than1.25 KW (about 770 W for the pressurization and less than 480 W for thethree valves and air fan). The energy available for outside of thesystem use is thus about 16.75 KW from this transient pressure workprocess.

In some embodiments, the systems and processes described herein cantherefore be substantially closed systems, operated without productionof any waste stream or pollution, having no carbon dioxide or othergaseous emissions, and no liquid, particulate, or other solid emissions,although one environmental effect may be temporary cooling of whateversubstance is used as the heat source for reheating the circulatingliquid. But, even then the net effect on the overall environment impactstandpoint can be zero or substantially near zero in some embodiments,due at least in part to the fact that the energy extracted eventuallyresults in a return to the overall environment through heat and frictionor other mechanisms. Further, temporary cooling does not even occur ifsources with large amounts of available heat energy are used such as theatmospheric air, the earth, or ocean water. Thus, outside of theimmediate local effect of the cooled heat source that may be caused bylarge power systems, which can be easily remedied with proper design,the systems and processes of the present disclosure can have essentiallyno negative effect on the environment.

Of course, it is to be understood that the above-described arrangementsare only illustrative of the application of the principles of thepresent invention. Numerous modifications and alternative arrangementsmay be devised by those skilled in the art without departing from thespirit and scope of the present invention and the appended claims areintended to cover such modifications and arrangements. Thus, while thepresent invention has been described above with particularity and detailin connection with what is presently deemed to be the most practical andpreferred embodiments of the invention, it will be apparent to those ofordinary skill in the art that numerous modifications, including, butnot limited to, variations in size, materials, shape, form, function andmanner of operation, assembly and use may be made without departing fromthe principles and concepts set forth herein.

What is claimed is:
 1. A transient liquid pressure power generationsystem, comprising: a liquid source; a transient pressure drive devicefluidly coupled to the liquid source to receive liquid from the liquidsource, the transient pressure drive device comprising a drivecomponent, and a transient wave producing element to cause a highpressure transient wave in the liquid traveling toward the liquid sourceto operate the drive component; and a heat source fluidly coupled to thetransient pressure drive device and the liquid source to receive liquidfrom the transient pressure drive device and heat liquid returning tothe liquid source.
 2. The system of claim 1, wherein liquid is gravityfed to the transient pressure drive device from the liquid source. 3.The system of claim 1, further comprising a pump to deliver liquid tothe transient pressure drive device.
 4. The system of claim 1, whereinthe drive component comprises a ram piston.
 5. The system of claim 1,wherein the drive component comprises a ram turbine.
 6. The system ofclaim 1, wherein the transient wave producing element comprises a valveor a piston to cause the high pressure transient wave.
 7. The system ofclaim 1, wherein the transient pressure drive device comprises a liquidconduit fluidly coupled to the liquid source, and configured such thatthe high pressure transient wave travels through the liquid conduittoward the liquid source and return to do work on the drive component.8. The system of claim 7, wherein the transient wave producing elementis disposed in the liquid conduit.
 9. The system of claim 8, wherein thetransient wave producing element is disposed in the conduit proximatethe liquid source to reflect pressure to the drive component.
 10. Thesystem of claim 8, wherein the transient wave producing element isdisposed in the conduit proximate the drive component.
 11. The system ofclaim 8, wherein the liquid conduit comprises a transition surfacebetween a first cross-sectional area and a second cross-sectional areaoperable to reflect at least a portion of a transient pressure wave inthe liquid traveling through the liquid conduit.
 12. The system of claim11, wherein the transition surface is configured to reflect thetransient pressure wave in a direction of fluid flow from the liquidsource.
 13. The system of claim 11, wherein the transition surface isconfigured to reflect the transient pressure wave in a directionopposite of fluid flow from the liquid source and facilitatetransmission of a higher transient pressure wave past the transitionsurface in a direction of fluid flow from the liquid source.
 14. Thesystem of claim 11, wherein the liquid conduit comprises a secondtransition surface between the second cross-sectional area and a thirdcross-sectional area operable to reflect at least a portion of thetransient pressure wave toward the first transition surface.
 15. Thesystem of claim 7, wherein the transient pressure drive device comprisesa fluid chamber in the liquid conduit, the fluid chamber containing acompressible fluid to absorb and reflect at least a portion of atransient pressure wave in the liquid traveling through the liquidconduit.
 16. The system of claim 15, wherein the fluid chamber isdisposed in the liquid conduit proximate the liquid source.
 17. Thesystem of claim 15, wherein the fluid chamber is disposed in the liquidconduit proximate the drive component.
 18. The system of claim 15,wherein the drive component comprises the fluid chamber.
 19. The systemof claim 7, wherein the transient pressure drive device furthercomprises a bypass line and a bypass valve associated with the bypassline, wherein the bypass valve is operable alternately to open to divertliquid from the drive component back to the liquid source and to closeto initiate the high pressure transient pressure wave in the liquid. 20.The system of claim 1, wherein the transient pressure drive device isconfigured to progressively reduce a load on the drive component. 21.The system of claim 1, further comprising a pressure chamber to deliverliquid to the transient pressure drive device.
 22. The system of claim21, further comprising a pressurized air cylinder, and a piston and rodassembly operable with the pressure chamber to facilitate entry ofliquid to the pressure chamber from the liquid source and to interactwith a transient pressure wave in the liquid.
 23. The system of claim 1,wherein the heat source comprises a heat exchanger.
 24. The system ofclaim 1, wherein the heat source comprises a heater.
 25. A transientliquid pressure drive device, comprising: a liquid conduit fluidlycoupleable to a liquid source to receive liquid from the liquid source;a drive component operable to generate power from a transient pressurewave; and a transient pressure producing element operable to cause atransient pressure wave in the liquid to operate the drive component.26. A method of generating power with a liquid, comprising: obtaining aliquid having a velocity or pressure; conveying the liquid through aconduit; causing a high pressure transient wave in the liquid within theconduit; utilizing the high pressure transient wave to perform work; andheating the liquid.